Camera featuring a single drive source and a plurality of selectable drive transmission mechanisms

ABSTRACT

A camera includes a plurality of camera operation mechanisms, a sun gear which rotates by means of a motor, a planetary gear which revolves around the sun gear, and a plurality of output gears each capable of meshing with the planetary gear by means of revolution of the planetary gear. The plurality of output gears transmit power to the plurality of camera operation mechanisms, respectively. A holding member is switchable from a first state, in which the planetary gear is allowed to revolve freely, to a second state, in which the planetary gear is held at a revolution position where the planetary gear is in mesh with one of the plurality of output gears. A controller causes the planetary gear to revolve so as to mesh with a selected one of the plurality of output gears, and switches the holding member from the first state to the second state, after completion of a power transmitting operation.

The present application is a divisional application of U.S. patentapplication Ser. No. 09/014,096 filed Jan. 27, 1998, which is adivisional application of U.S. patent application Ser. No. 08/731,920filed Oct. 22, 1996, now U.S. Pat. No. 5,752,096 issued May 12, 1998,which is a continuation of U.S. patent application Ser. No. 08/580,276filed Dec. 27, 1995 (abandoned), which is a continuation of U.S. patentapplication Ser. No. 08/323,710 filed Oct. 18, 1994 (abandoned), whichis a continuation of U.S. patent application Ser. No. 07/834,167 filedFeb. 11, 1992 (abandoned).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an optical apparatus capable ofselectively supplying power from a drive source to a plurality of powertransmission mechanisms.

2. Description of the Related Art

A conventional general planetary gear mechanism includes, as shown inFIGS. 32(a) and 32(b), a sun gear 101 which rotates by means of acertain power, an arm 102 which rotates about a shaft 108 common to thesun gear 101 independently of the sun gear 101, and a planetary gear103, which is secured to the arm 102 by a shaft 107 for rotation withrespect to the arm 102 against the resistance of a spring 106 and inmesh with the sun gear 101.

In the shown mechanism, the planetary gear 103 can turn (revolve) aboutthe sun gear 101, and can also turn (rotate) on its axis.

Such a planetary gear mechanism is generally used for a switchingmechanism for selectively transmitting power for winding or rewinding offilm in a camera or the like. In the planetary gear mechanism, as shownin FIG. 33, the extent of revolution of the planetary gear 103 is not anangle of 360 degrees, and is limited by two gears: a gear 104 fortransmitting power to a winding system and a gear 105 for transmittingpower to a rewinding system. In practice, however, since the gears maybite into each other, the extent of revolution of the planetary gear 103is limited by bringing the shaft 107 of the planetary gear 103 intoabutment with a portion 109 or 110. In this arrangement, if the sun gear101 rotates toward the left as viewed in FIG. 33, the planetary gear 103meshes with the gear 105 to cause the gear 105 to rotate in thedirection indicated by a solid arrow. If the sun gear 101 rotates towardthe right, the planetary gear 103 meshes with the gear 104 to cause thegear 104 to rotate in the direction indicated by a dashed arrow. Anumber of states brought about by the above-described operation areenumerated below:

1) Whether power is switched to the gear 104 or 105 is determined onlyby whether the sun gear 101 rotates toward the right or the left.

2) Each of the gear 104 and the gear 105 to which power is transmittedrotates in one direction only. That is to say, two lines are availablefor force transmission.

3) During power transmission or if gear backlash occurs in the directionof power transmission, the abutment portion 109 is subjected to a forceF-109 from the shaft 107. In the opposite case, the abutment portion 110is subjected to a force F-110.

4) If the planetary gear 103 is switched from the gear 105 to the gear104 while power is being transmitted to the gear 105 as shown in FIG.33, the planetary gear 103 only rotation (left-handed rotation)immediately after the right-handed rotation of the sun gear 101 isstarted, until the backlash is removed and the force F-109 disappears.Subsequently, the planetary gear 103 starts revolution.

The reasons why only two lines are available for force transmission asdescribed above in Paragraph 2) are:

a) Since the conventional planetary gear mechanism is arranged in such amanner that the extent of revolution of the planetary gear 103 islimited by the gear 104 and the gear 105 as shown in FIG. 33, it isimpossible to mesh the planetary gear 103 with any gear other than thegear 104 and the gear 105.

b) The direction of rotation of either one of the gears 104 and 105 isthe direction of power transmission, while the direction of rotation ofthe other is the direction in which the planetary gear 103 is switched.As a result, either one of the gears 104 and 105 can transmit a force inone direction only.

For the above reasons, the number of transmission lines of force is two.

To realize the number of transmission lines of force which is greaterthan two, a planetary gear mechanism such as that shown in FIG. 34 mayalso be considered. In the shown mechanism, a plurality of (four, inthis example) gears 111 a to 111 d are disposed circumferentially, andthe positional relation between each of the gears 111 a to 111 d, thesun gear 101 and the planetary gear 103 is selected so that they can bearranged in a straight line to prevent each of the gears 111 a to 111 dfrom hindering the planetary gear 103. Stoppers 112 a to 112 d each ofwhich prevents the left-handed revolution of the planetary gear 103 aredisposed in the vicinity of the respective gears 111 a to 111 d formovement toward and away from the planetary gear 103. In thisarrangement, by causing the sun gear 101 to rotate toward the right, agear with which the planetary gear 103 is to be meshed is selected fromamong the gears 111 a to 111 d, and by causing the sun gear 103 torotate toward the left, the shaft 107 is brought into abutment with theassociated one of the stoppers 112 a to 112 d so that force istransmitted to the selected one of the gears 111 a to 111 d. However,this arrangement merely solves the problem stated in paragraph a), andthe problem of paragraph b) remains. The direction in which force can betransmitted to each of the gears 111 a to 111 d is limited to onedirection only as shown in FIG. 34, and no force can be transmittedthrough rotation in the opposite direction.

However, the arrangement of FIG. 34 which uses four gears 111 a to 111 dand four gear trains which can be coupled to the respective gears 111 ato 111 d has a problem: Since force can be transmitted in one directiononly, it is difficult to use the arrangement as a mechanism whichrequires rotation in both right-handed and left-handed directions. Ifthere is a planetary gear mechanism which can transmit force in bothright-handed and left-handed direction by means of one gear train, it ispossible to selectively transmit power from a single power source to aplurality of gear trains by causing a sun gear to rotate toward theright or the left.

FIG. 35 shows a model diagram of the basic concept of such a planetarygear mechanism.

In the arrangement shown in FIG. 35, the revolution of the planetarygear 103 is stopped by an arbitrary one of stoppers 113 a to 113 d andthe adjacent one of stoppers 114 a to 114 d, whereby both theright-handed and left-handed revolutions of the planetary gear 103 arestopped and power can be transmitted to the desired one of the gears 111a to 111 d in either direction of rotation thereof.

Consideration will be given below to a case where, in such anarrangement, an element to which power is to be transmitted is switched,for example, from the gear 111 a which is presently in mesh with theplanetary gear 103 to the gear 111 b. It is assumed that the directionof rotation of the output gear 111 b after switching is desired to bemade left-handed (the direction of rotation of the sun gear 101 is alsomade left-handed).

In this case, the sun gear 101 is made to rotate toward the right tocause the planetary gear 103 to revolve toward the right and mesh withthe gear 111 b. However, since it is desired that the direction ofrotation of the output gear 111 b be made left-handed, it is necessaryto cause the sun gear 101 to rotate in the opposite direction (towardthe left) after the gears 103 and 111 b have meshed with each other.This means that at the time when the gears 103 and 111 b mesh with eachother, a driving force is instantaneously transmitted to the gear 111 bin the direction opposite to the desired direction. At this time, if thegear 111 b is coupled to, for example, a power transmission mechanismfor effecting zooming, the angle of view will shift in the directionopposite the desired direction and a photographer will have a sense ofincompatibility.

To realize the above-described mechanism, the following problems mustalso be solved.

1) It is necessary to design a mechanism in which while the planetarygear 113 is revolving to mesh with any one of the gears 111 a to 111 d,the stoppers 113 a to 113 d and 114 a to 114 d are made to move backwardso as not to limit the revolution of the planetary gear 113.

2) If power transmission is performed or backlash occurs with theplanetary gear 103 meshed with any one of the gears 111 a to 111 d, aforce F-115 or F-116 will be generated and applied to the adjacent oneof the stoppers 113 a to 113 d or 114 a to 114 d. Each of the forcesF-115 and F-116 must be controlled so as not to influence the revolutionof the planetary gear 103.

The state shown in FIG. 35 will be considered below. In FIG. 35, thegear 111 a is being made to rotate toward the left, or the sun gear 101is stopped with the gear 111 a driven to rotate toward the left. Duringthis time, the stopper 113 a stops the shaft 107 from rotating aroundthe sun gear 101 toward the left. To switch the line of powertransmission, if the stopper 113 a in that state is released by means ofthe mechanism mentioned above in paragraph 1), the planetary gear 103will revolve independently toward the left by the force indicated by thearrow F-115. As a result, the control of the planetary gear 103 ishindered. For this reason, it is necessary to design a mechanism capableof controlling the revolving force of the planetary gear 103 withouterror.

FIG. 35 also shows the state wherein the driving force of the sun gear101 which is rotating toward the left is being transmitted to the gear111 a. In this state, since none of the other gears 111 b to 111 d ismeshed with the planetary gear 103, there is not a member which limitstheir rotation. In a case where an element to which power is to betransited from an arbitrary one of the gears 111 b to 111 d, forexample, the gear 111 c, is a mechanism which may be subjected to anexternal force by accident, for example, a zoom barrel mechanism in acamera, if a certain external force is applied to the zoom barrelmechanism from the outside of the camera, the zoom barrel mechanism willmove independently. Of course, if the mechanism to which power is to betransmitted from the gear 111 a is easily subjected to an external forceby accident, when the planetary gear 103 revolves to another positionafter the completion of power transmission, a similar problem willarise.

In the arrangement shown in FIG. 35, the revolution of the planetarygear 103 is stopped by bringing any one of the stoppers 113 a to 113 dand 114 a to 114 d into abutment with the shaft 107, and the planetarygear 103 meshes with an arbitrary one of the gears 111 a to 111 d. Therevolving force of the planetary gear 103, which is generated in theright-handed or left-handed direction during power transmission iscancelled by limiting the revolution of the shaft 107 in the samedirection by means of the associated one of the stoppers 113 a to 113 dand 114 a to 114 d. In such an arrangement, if it is desired that theplanetary gear 103 be made to mesh with another gear among the gears 111a to 111 d by causing the planetary gear 103 to revolve toward the rightor the left, it is necessary to cause the stoppers 113 a to 113 d and114 a to 114 d to move backward so as not to limit the revolution of theshaft 107. In other words, a mechanism is needed in which none of thestoppers 113 a to 113 d and 114 a to 114 d interfere with the shaft 107rotating around the sun gear 101. To realize such a mechanism, it isnecessary to adopt one of the following arrangements:

A) An arrangement in which the stoppers 113 a to 113 d and 114 a to 114d can move backward from the shaft 107.

B) An arrangement in which the shaft 107 can move backward from thestoppers 113 a to 113 d and 114 a to 114 d.

However, the arrangement of paragraph A) has the followingdisadvantages. Four pairs of stoppers must be operated, and if they areto be operated separately, a complicated construction is needed. If thefour pairs are to be operated simultaneously, the size of the entiremechanism must be made large, with the result that the mass increasesand the response of control deteriorates.

The arrangement of paragraph B) has also a number of problems. Since theshaft 107 rotates with the revolution of the planetary gear 103, theposition of the shaft 107 during rotation must be detected. To operate amember which changes its position while rotating every moment, acomplicated construction will be needed.

In the arrangement shown in FIG. 35, the revolution of the planetarygear 103 is stopped in such a way that the stoppers 113 a to 113 d and114 a to 114 d which are arranged for movement toward and away from theshaft 107 are selectively brought into abutment with the shaft 107.However, if the stoppers 113 a to 113 d and 114 a to 114 d move backwardand stops limiting the shaft 107, the revolution of the planetary gear103 is not limited at all and the planetary gear 103 revolvesunlimitedly as long as the sun gear 101 continues rotating. In such anarrangement, if it is desired to cause the planetary gear 103 to meshwith an arbitrary one of the gears 111 a to 111 d so that powertransmission is performed with the revolution limited, it is necessaryto use a device for detecting in which position the planetary gear 103is revolving or which of the gears 111 a to 111 d is in mesh with theplanetary gear 103. In this case, it is desirable to use a devicecapable of detecting the position of the planetary gear 103 duringrevolution as an absolute position. However, the number of suchdetecting devices must be increased according to the number of gears forpower (in FIG. 35, four for the gears 111 a to 111 d), with the resultthat the complexity of the apparatus will increase.

For the above-described reasons, it is common practice to adopt a methodof preparing a pulse disc (not shown) secured to an arm 102 or the shaft107 and provided with a pattern of bright and dark segments provided anddetecting the amount of rotation of the pulse disc by means of aphotocoupler or the like, thereby solving the above-describeddisadvantages. More specifically, an arrangement adopting such a methodmakes it possible to reduce the number of parts used and also to use asimple detection method which merely detects “bright” and “dark”signals. The bright and dark segments may be formed so that the statewhere the planetary gear 103 is in mesh with any one of the gears 111 ato 111 d can be distinguished from the state where the planetary gear103 is in mesh with none of the gears 111 a to 111 d.

In the above-described method of finding a position from the “bright”and “dark” signals, since a relative position is only detected, it isnecessary to determine the first position (initial position) in advance,and this initial position serves also as a revolution abutment positionbeyond which the planetary gear 103 does not revolve.

Referring to the arrangement shown in FIG. 33, the revolution abutmentposition corresponds to the position where the planetary gear 103 ismeshed with the gear 104 or 105. If the operation of bringing theplanetary gear 103 into abutment with the gear 104 or 105 to find theinitial position, the gear 104 or 105 may be rotated by accident at therevolution abutment position (initial position). It is necessary,therefore, to prevent such accidental rotation. Similarly, in thearrangement shown in FIG. 35, while the planetary gear 103 is makingrotation with its revolution limited at the revolution abutmentposition, it is necessary to prevent the rotation from being transmittedto any of the gears 111 a to 111 d.

In the arrangement shown in FIG. 35, to detect the position of theplanetary gear 103 during revolution, a method may be employed in whicha pulse disc (not shown) provided with a pattern consisting of brightand dark segments is secured to the arm 102 or the shaft 107 and theamount of rotation of the pulse disc is detected by means of aphotocoupler or the like. In this method, the number of parts can bereduced, and it is only necessary to detect “bright” and “dark” signals.The “bright” and “dark” segments of the pattern may be provided so thatthe state of the planetary gear 103 being meshed with any one of thegears 111 a to 111 d can be distinguished from the state of theplanetary gear 103 being meshed with none of them. In the arrangement ofFIG. 35, since the planetary gear 103 can selectively mesh with fourgears, if the “bright” segments are made to correspond to the state ofthe planetary gear 103 being in mesh, four “bright” segments may beprovided on the pulse disc. In a method of finding a position whiledetecting a relative transition such as a transition between brightnessand darkness, it is necessary to determine the first position (initialposition) as shown in FIG. 36. The sun gear 101 is made to rotateunconditionally during a predetermined time period in one direction tocause the planetary gear 103 to revolve, thereby bringing the shaft 107into abutment with a revolution abutment member 117. The position atwhich the shaft 107 comes into abutment with the revolution abutmentmember 117 is determined as the initial position. (The revolutionabutment member 117 may be provided not in the shown position but in anyposition, and any of the stoppers 113 a to 113 d and 114 a to 114 d canalso be easily used as the revolution abutment member 117.) After theinitial position has been determined, the amount of revolution of theplanetary gear 103 is detected on the basis of the relative transitionof a pulse signal and the planetary gear 103 is made to mesh with anarbitrary one of the gears 111 a to 111 d, and the rotation of the sungear 101 is selectively transmitted to the meshed one of the gears 111 ato 111 d. In the above-described mechanism in which the revolution ofthe planetary gear 103 is controlled not sequentially in time butselectively while the position of the planetary gear 103 duringrevolution is being detected on the basis of the relative transitionobtained from a pulse transition, the initial position is essential tothe control of the revolution of the planetary gear 103. Accordingly,if, in each power transmission operation, power can be transmitted bybringing the planetary gear 103 into mesh with an arbitrary one of thegears 111 a to 111 d after the confirmation of the initial position,power transmission with improved reliability will be able to berealized.

However, if such “initial positioning” is performed each time an elementto which power is to be transmitted is changed, since the “initialpositioning” operation itself is not an actual operation for powertransmission but a switching operation, a switching operation ofextremely long time will be needed and no desired control will be not beable to be achieved; for example, the response speed of a photographicoperation is impaired.

In general and in a camera provided with a power dividing deviceemploying a planetary gear mechanism, after the completion ofphotography, a planetary gear is made to mesh with an output gearcoupled to a film transportation mechanism and film is wound by anexposed frame. Subsequently, in general and, for example, in a cameraprovided with a zooming mechanism (or a focal-length varying mechanismwhich is switchable between two different focal lengths), the planetarygear is brought into mesh with the output gear coupled to the zoomingmechanism in preparation for the next photographic cycle. However, inthe case of a camera capable of continuous-shooting photography, if theabove-described operation is performed, the response speed of aphotographic operation is impaired.

It has conventionally been proposed to provide several kinds of systemscapable of detecting an abnormality of a camera and inhibiting theoperation of the camera or performing the same operation again.

In one typical example of such a system, if a position detecting meansdetects that shutter blades do not open, the subsequent shutter releaseoperation is inhibited. In another example, if it is detected that asignal indicative of the feed of a perforation has not come during theautomatic loading of a film, an error indication of the occurrence of anautomatic-loading error is displayed.

In either example, the above-described operation is merely subjected toinhibition because the operation is a relatively simple operation andbecause when an error occurs in such an operation, even if the sameoperation is performed again, the probability that a similar error willoccur again is extremely high.

Cameras provided with an increasingly large number of functions haverecently been developed, and a complicated mechanism such as a zoomingmechanism or a retracting mechanism may be incorporated or a mechanismfor dividing power from a single driving source among various outputelements may also be adopted for the purpose of making a camera bodymore compact. As a result, the sequence of operations has become morecomplex and attention has been drawn to the following two seriousproblems:

1) The length of the sequence increases, and hence the time period forthe sequence to proceed from beginning to end becomes long. As a result,the influence of the outside world on a camera becomes serious and, forexample, during the operation of the camera, an unduly large force maybe applied to a zooming mechanism or the like by the application of anexternal force, or the probability that noise may be introduced into acontrol part becomes high.

2) With an increase in the complexity of each device, an operation errorof a device which seldom takes place and hence may be ignored in asingle-function apparatus becomes more and more serious. A typicalexample of the operation error is an operation error due to the bitingof the teeth tips of a planetary gear and an output gear into eachother.

In a conventional camera provided with an autofocus (AF) device, when ashutter button is pressed to its first stroke position, a distancemeasurement operation is performed. Then, when the shutter button ispressed to its second stroke position, a photographic lens is driven tomove from its initial position to a desired position on the basis of thedistance measurement information obtained from the distance measurementoperation. Subsequently, the shutter is made to open and close, andfurther after the completion of the resetting operation of causing thephotographic lens to return to the initial position, a film windingoperation is performed.

In recent years, high-magnification zoom lenses have been incorporatedinto compact AF cameras of the type described above. Accordingly, toachieve a predetermined photographic resolution in such an AF camera,for example, if a stepping motor is used to drive the photographic lens,it is necessary to increase the number of driving steps in which thephotographic lens is driven during AF driving, compared to asingle-focus camera.

For this reason, there is a tendency for a longer time to be taken toset the photographic lens before a shutter opening and closingoperation. This tendency naturally leads to the problem of a shuttertime lag. In addition, since the driving sound of the stepping motor orthe shutter is not too large in itself, there is no substantial drivingsound due to a shutter release operation when the shutter button reachesthe second stroke position. After the completion of the shutter openingand closing operation, the photographic lens is reset to the initialposition, and when a film winding operation is started, the drivingsound is generated for the first time.

Accordingly, in a considerably noisy circumstance, a photographer cannothear a shutter release sound and often becomes uneasy about the state ofthe shutter release operation and the like. In other words, even thoughexposure is completed at the timing of the shutter opening and closingoperation, the photographer hears the sound of a film winding operationand can feel that photography is completed. As a result, thephotographer is afraid that the shutter release operation might haveended or the camera might have failed, and feels anxious during theperiod from the time he operates a shutter release button until he hearsthe sound of a film winding operation.

FIG. 35 shows the state wherein the driving force of the sun gear 101which is rotating toward the left is being transmitted to the gear 111a. In this state, since none of the other gears 111 b to 111 d is meshedwith the planetary gear 103, there is not a member which limits theirrotation. In a case where an element to which power is to be transmittedfrom an arbitrary one of the gears 111 b to 111 d, for example, the gear111 c, is a mechanism which may be subjected to an external force byaccident, for example, a focal-length varying mechanism in a camera, ifa certain external force is applied to this mechanism from the outsideof the camera, the mechanism will move independently. Of course, if themechanism to which power is to be transmitted from the gear 111 a iseasily subjected to an external force by accident, when the planetarygear 103 revolves to another position after the completion of powertransmission, a similar problem will arise.

To solve the above-described problem, after the completion oftransmission, the planetary gear 103 may be made to selectively meshwith a gear which is coupled to a mechanism which is easily subjected toan external force by accident, and this meshed state may be held.However, the method of causing the planetary gear 103 to selectivelymesh with the gear has the following problems:

In the arrangement shown in FIG. 35, the stoppers 113 a to 113 d and 114a to 114 d serve to lock the revolution of the planetary gear 103, asdescribed previously, and is arranged for movement toward and away fromthe planetary gear 103 and the shaft 107. It is assumed here that in acase where the planetary gear 103 is allowed to revolve with thestoppers 113 a to 113 d and 114 a to 114 d moved backward, the planetarygear 103 is made to mesh with the gear 111 a to prevent idling of themechanism coupled to the gear 111 a, as shown in FIG. 36.

In this case, a device (not shown) detects that the planetary gear 103has revolved up to and meshed with the gear 111 a, and the stoppers 113a and 114 a are made to move forward as shown, thereby locking therevolution of the planetary gear 103. At the moment the revolution ofthe planetary gear 103 is locked, it starts rotating. If the rotation ofthe sun gear 101 is stopped at the moment the revolution of 103 islocked, the rotation of the sun gear 101 causes the gear 111 a torotate. Accordingly, if the timing to stop the rotation of the sun gear101 and the timing to perform locking of the revolution by the stoppers113 a and 114 a are not accurately established, the mechanism coupled tothe gear 111 a will move if it is a “mechanism which is capable offunctioning even during a state other than an abutment state”.

A typical example of a mechanism utilizing only the abutment state is amechanism utilizing a telephoto end or a wide-angle end, as in the caseof the lens barrel of a bifocal camera. A typical example of themechanism which is capable of functioning even during a state other thanthe abutment state is a mechanism capable of performing a zoomingfunction even if the lens barrel is in the middle position other thanthe telephoto end and wide-angle end positions, as in a camera having azooming mechanism.

If the planetary gear 103 is made to mesh with a gear coupled to theabove-described zooming mechanism, at the moment the stoppers 113 a and114 a for preventing idling engage with the shaft 107, the zoomingmechanism may move accidentally. To prevent occurrence of such aproblem, the rotation of the planetary gear 103 may be stopped beforethe locking of the revolution is started. This state is substantiallyidentical to the state of the stoppers 113 a and 114 a being omitted,and it may be impossible to lock the zooming mechanism or to performpower transmission.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide anoptical apparatus arranged to cause a planetary gear to selectively meshwith at least two output gears by causing the planetary gear to revolveby means of the rotation of a sun gear, the optical apparatus includinga member which follows the revolution of the planetary gear and which isarranged for movement along a thrust axis in opposite directions, one ofthe aforesaid at least two output gears with which the planetary gear ismeshed being capable of rotating selectively in forward and reversedirections by means of the forward or reverse rotation of the planetarygear due to the forward or reverse rotation of the sun gear, theplanetary gear being meshed with the aforesaid output gear with theaforesaid member being held in a predetermined position by holdingmeans.

Another object of the present invention is to provide an opticalapparatus arranged to cause a planetary gear to mesh with a selectedoutput gear and selectively transmit the power of the sun gear to theselected output gear. In the optical apparatus, it is determined whetherthe direction in which the planetary gear is made to revolve forselection of the output gear is the same as the direction in which theoutput gear rotates after the planetary gear has been held by holdingmeans, and if both directions differ, the direction of rotation of theplanetary gear is made coincident with the direction of rotation of theoutput gear and, then, the planetary gear and the output gear are madeto mesh with each other.

The above and other objects, features and advantages of the presentinvention will become apparent from the following detailed descriptionof preferred embodiments of the present invention, taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic exploded perspective view of the power dividingdevice of a camera, showing a first embodiment of the present invention;

FIG. 2 is a diagrammatic vertical sectional view of the power dividingdevice of a camera, showing the first embodiment of the presentinvention;

FIG. 3 is a diagrammatic plan view of the power dividing device of acamera, showing the first embodiment of the present invention;

FIG. 4 is a fragmentary enlarged view illustrating the shapes of a crownstopper, a holding stopper and a rotation-stopping arm in the firstembodiment of the present invention;

FIGS. 5(a), 5(b) and 5(c) are a plan view and vertical sectional views,respectively, showing the state in which a planetary gear is located ina region {circle around (8)} in the first embodiment of the presentinvention;

FIGS. 6(a), 6(b) and 6(c) are a plan view and vertical sectional views,respectively, showing the state in which the planetary gear is switchedfrom a region {circle around (4)} to a region {circle around (5)} in thefirst embodiment of the present invention;

FIGS. 7(a), 7(b) and 7(c) are a plan view and vertical sectional views,respectively, showing the state in which the planetary gear is locatedin the region X in the first embodiment of the present invention;

FIGS. 8(a), 8(b) and 8(c) are a plan view and vertical sectional views,respectively, showing the state of the power dividing device immediatelybefore the planetary gear enters the region {circle around (5)} in thefirst embodiment of the present invention;

FIGS. 9(a), 9(b) and 9(c) are plan views and a vertical sectional view,respectively, showing the state in which the planetary gear is locatedin the region {circle around (5)} in the first embodiment of the presentinvention;

FIGS. 10(a) and 10(b) are vertical sectional views, respectively,showing the state of the power dividing device immediately before theplanetary gear exits from a particular region in the first embodiment ofthe present invention;

FIG. 11 is a chart illustrating a pulse waveform which serves as aposition signal indicative of the position of the planetary gear in thefirst embodiment of the present invention;

FIGS. 12(a) and 12(b) are schematic views which serve to illustrate an“exit operation” in the first embodiment of the present invention;

FIGS. 13(a) and 13(b) are timing charts respectively showing theoperations shown in FIGS. 12(a) and 12(b);

FIGS. 14(a) and 14(b) are schematic views which serve to illustrate an“entrance operation” in the first embodiment of the present invention;

FIGS. 15(a) and 15(b) are timing charts respectively showing theoperations shown in FIGS. 14(a) and 14(b);

FIG. 16 is a schematic cross sectional view showing the mechanicalconstruction of a camera in which the device according to the firstembodiment of the present invention is incorporated;

FIG. 17 is a circuit block diagram showing the essential construction ofthe camera in which the device according to the first embodiment of thepresent invention is incorporated;

FIG. 18 is a flowchart showing the main operation of the control circuit24 of FIG. 17;

FIG. 19 is a flowchart showing the operation named “INITIAL POSITIONING”of the control circuit 24 of FIG. 17;

FIG. 20 is a flowchart showing the operation named “ENERGIZE MOTOR INREVERSE DIRECTION” of the control circuit 24 of FIG. 17;

FIG. 21 is a flowchart showing the operation named “COUNT PULSE” of thecontrol circuit 24 of FIG. 17;

FIG. 22 is a flowchart showing the operation named “POWER DIVIDING” ofthe control circuit 24 of FIG. 17;

FIG. 23 is a flowchart showing the operation named “OPERATION FOR MOVINGLENS BARREL FORWARD” of the control circuit 24 of FIG. 17;

FIG. 24 is a flowchart showing the operation named “OPERATION FOR MOVINGLENS BARREL BACKWARD” of the control circuit 24 of FIG. 17;

FIG. 25 is a flowchart showing the operation named “AUTOMATIC LOADING”of the control circuit 24 of FIG. 17;

FIG. 26 is a flowchart showing the operation named “TELEPHOTO ZOOMING”of the control circuit 24 of FIG. 17;

FIG. 27 is a flowchart showing the operation named “WIDE-ANGLE ZOOMING”of the control circuit 24 of FIG. 17;

FIG. 28 is a flowchart showing the operation named “WINDING” of thecontrol circuit 24 of FIG. 17;

FIG. 29 is a flowchart showing the operation named “REWINDING” of thecontrol circuit 24 of FIG. 17;

FIG. 30 is a flowchart showing the operation named “ZERO POSITION” ofthe control circuit 24 of FIG. 17;

FIG. 31 is a table showing the symbols used in the explanations ofvarious kinds of operations of the control circuit 24 of FIG. 17, aswell as the relationships between driving operations, dividing positionsand motor directions;

FIGS. 32(a) and 32(b) are a schematic perspective view and a schematicvertical sectional view, respectively, showing the construction of aconventional planetary gear mechanism;

FIG. 33 is a schematic plan view showing a planetary gear mechanismwhich constitutes an essential portion of the construction shown inFIGS. 32(a) and 32(b) and an output gear to which power is to betransmitted from the planetary gear mechanism;

FIG. 34 is a schematic plan view which serves to illustrate the casewhere elements to which power is to be transmitted from the planetarygear mechanism of FIG. 33 are arranged as four lines so that power canbe transmitted in four directions;

FIG. 35 is a schematic plan view which serves to illustrate the casewhere elements to which power is to be transmitted from the planetarygear mechanism of FIG. 33 are arranged as four lines so that power canbe transmitted in eight directions;

FIG. 36 is a schematic plan view showing an example in which the powerdividing device of FIG. 35 is provided with limiting members whichdefine an initial position and a revolution abutment position for therevolution of the planetary gear;

FIG. 37 is a schematic view showing the cross section of a photographiclens barrel and a specific arrangement of elements disposed in thevicinity of the photographic lens barrel in a camera according to asecond embodiment of the present invention;

FIG. 38 is a circuit block diagram schematically showing theconstruction of the camera according to the second embodiment;

FIG. 39 is a flowchart showing an operation for causing the lens barrelto retract, executed by the control circuit of FIG. 38;

FIG. 40 is a flowchart showing an operation for causing the lens barrelto move forward, executed by the control circuit of FIG. 38;

FIG. 41 is a flowchart showing the main operation of the control circuit24 according to a third embodiment;

FIG. 42 is a circuit block diagram showing the arrangement of theessential parts of a camera according to a fourth embodiment;

FIG. 43 is a flowchart showing the operation of the control circuit ofFIG. 42; and

FIG. 44 is a schematic plan view showing essential parts in the fourthembodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described belowwith reference to the accompanying drawings.

FIG. 16 is a schematic cross-sectional view showing the mechanicalessential parts of a camera provided with a power dividing deviceaccording to a first embodiment of the present invention.

The arrangement shown in FIG. 16 includes a sun gear 6, a planetary gear7, and output gears 9 a to 9 d each of which constitutes a power sourcewhich will be described later. These elements 6, 7 and 9 a to 9 dconstitute part of the power dividing device.

The output gear 9 a causes a gear train 310 a (not shown in detail inFIG. 16) to rotate a helicoid gear 310 operative to effect forwardmovement or backward movement of a lens barrel 314 which holds lensdriving mechanisms such as a lens tube 316 and a cam ring 315.

The output gear 9 b causes a gear train 311 a (not shown in detail inFIG. 16) to rotate a bayonet ring 311 which serves to secure the lensbarrel 314 placed in its forward position to a body 317 and inhibit thelens barrel 314 from moving toward its retracted position.

The output gear 9 c causes a gear train 312 a (not shown in detail inFIG. 16) to rotate a zoom driving gear 312 which causes the cam ring 315in the lens barrel 314 to move, thereby effecting zooming.

The output gear 9 d is meshed with a planetary gear 304 for filmtransportation via an arm 309. The elements 9 d, 304 and 309 constitutea planetary gear mechanism for film transportation, and the output gear9 d itself serves as a sun gear. The left-handed or right-handedrotation of the output gear 9 d causes a fork 306 or a spool 305 torotate selectively, thereby effecting winding of a film F from a filmcartridge 313 or rewinding of the film F into the film cartridge 313.

The construction of the power dividing device including the sun gear 6,the planetary gear 7 and the output gears 9 a to 9 d will be describedbelow with reference to FIGS. 1 to 3 and other associated figures.Throughout these figures, only the parts (gears, springs, etc.) requiredfor power division are shown, but for simplification of illustration,the other parts such as a base plate for mounting or positioning themare not shown.

As shown in FIGS. 1 and 3, the output gears 9 a to 9 d to which power isselectively transmitted from the planetary gear 7 are circumferentiallyarranged so that the planetary gear 7 can revolve through 360 degrees.Although four output gears are used in the shown embodiment, the numberof output gears is not limited to four, and two or more output gears maybe employed.

The planetary gear 7 is arranged to rotate about a planetary shaft 8 a,and the rotation of the planetary gear 7 on its axis undergoes a certaindegree of resistance due to a spring 8 b fitted onto the planetary shaft8 a. The planetary shaft 8 a and the planetary gear 7 are secured to arotating arm 5, and the sun gear 6 is disposed on the rotating arm 5.The sun gear 6 is arranged to rotate by the rotation of an output shaft3.

The output shaft 3 is made to rotate by the power of a motor 1. Sincethe output shaft 3 needs to have a certain degree of rotational torque,the power of the motor 1, which, in the first embodiment, is of a knowntype for use in a camera, is transmitted to the output shaft 3 through aspeed reducing mechanism 2.

The rotating arm 5 and the output shaft 3 are rotatably secured to abearing 4, and the rotating arm 5 and the output shaft 3 rotate insliding contact with the external and internal peripheries of thebearing 4, respectively. The bearing 4 is formed, as by insert molding,integrally with a base plate (not shown) having shafts to which theoutput gears 9 a to 9 b are rotatably secured respectively. A forcewhich causes the rotating arm 5 to rotate about the sun gear 6 isgenerated only by the revolving force of the planetary gear 7.

The rotating arm 5 has several erected portions, and each erectedportion 5 a has a hole. A rotation-stopping arm 12, which is disposedabove the rotating arm 5 as viewed in FIG. 1, has holes 12 b. Therotation-stopping arm 12 is secured rotatably with respect to therotating arm 5 by a rotating-arm shaft 13 a which is inserted throughthe holes, so that the rotation-stopping arm 12 is capable of swingingabout the rotating-arm shaft 13 a. Since the rotation-stopping arm 12swings in an approximately horizontal state, an end portion 12 c of therotation-stopping arm 12 c makes motion close to vertical motion (motionalong a thrust axis). The rotation-stopping arm 12 has a hole 12 a, andthe above-described planetary shaft 8 a is inserted through the hole 12a (the state shown in FIG. 2). In this state, since the hole 12 a has aslot-like shape, the planetary shaft 8 a does not restrict the verticalrotation of the rotation-stopping arm 12 (the vertical motion of the endportion 12 c) and can rotate the rotation-stopping arm 12 horizontallyin interlocked relation to the horizontal rotation of the rotating arm 5integral with the planetary shaft 8 a. A torsion spring 13 b is fittedonto the rotating-arm shaft 13 a and urges the end portion 12 c of therotation-stopping arm 12 in the upward direction.

A pulse disc 14 is disposed above the rotation-stopping arm 12. Erectedportions 5 b of the rotating arm 5 are respectively inserted through andfixed in holes 14 b formed in the pulse disc 14, and a cutout 8 d of theplanetary shaft 8 a is fixed in a slot 14 a, whereby the pulse disc 14rotates horizontally integrally with the horizontal rotation of therotating arm 5.

An arm 15 is disposed above the pulse disc 14 and is rotatably securedby an arm shaft 15 b which is fixed by a base plate (not shown). Atorsion spring 15 c which is similar to the torsion spring 13 b isfitted onto the arm shaft 15 b, and urges the arm 15 in the direction inwhich one end 15 a applies a force downward as viewed in FIG. 1 or 2. Aprojection 15 e is fixed to the end 15 a and urges a central portion 12d of the rotation-stopping arm 12 in the downward direction through alarge hole 14 c formed in the pulse disc 14.

A movable yoke 16 a of a plunger 16 is disposed at another end 15 d ofthe arm 15. When the plunger 16 is energized to pull the movable yoke 16a downward as viewed in FIG. 1 or 2, the projection 15 e moves upward asviewed in FIG. 1 or 2. The balance between the spring strength of thetorsion spring 13 b and that of the torsion spring 15 c is selected sothat the vertical motion of the rotation-stopping arm 12 can follow themotion of the projection 15 e of the arm 15.

The reason why the projection 15 e of the arm 15 presses the centralportion of the rotation-stopping arm 12 during the downward urgingthereof as viewed in FIG. 1 as well as several advantages obtainablefrom such an arrangement will be described below.

The center of the horizontal rotation of the rotation-stopping arm 12,which rotates in interlocked relation to the rotating arm 5 whichrotates horizontally in interlocked relation to the revolution of theplanetary gear 7, is positioned immediately above the output shaft 3,that is, the sun gear 6 (around the central portion 12 d in FIG. 1). Inwhatever position the planetary gear 7 is revolving, the central portion(12 d) of the rotation-stopping arm 12 coincides with the center ofrotation. Accordingly, in whatever position the planetary gear 12 islocated in interlocked relation to the sun gear 6, the planetary gear 7,the rotating arm 5 and the like (for example, any of the states shown inFIGS. 5(a) to 9(a)), the projection 15 e of the arm 15 can press thecentral portion 12 d under the same conditions and move the end portion12 c of the rotation-stopping arm 12 vertically. Accordingly, anoperation for bringing the end 12 c of the rotation-stopping arm 12 intoengagement with any one of the cutouts of a crown stopper 10 to stop therevolution of the planetary gear 7 and transmit power to any one of theoutput gears 9 a to 9 d, is implemented by a simple mechanism in whichthe projection 15 e of the arm 15 urges the central portion 12 d of therotation-stopping arm 12 irrespective of the state of rotation of therotation-stopping arm 12.

The crown stopper 10 and a holding stopper 11 are secured to a baseplate (not shown) on top of each other immediately above the outputgears 9 a to 9 d, that is, between the rotating arm 5 and therotation-stopping arm 12. Each of the stoppers 10 and 11 is providedwith cutouts each having a shape through which the end portion 12 c ofthe rotation-stopping arm 12 can pass.

As shown in FIG. 4 (a partial enlarged view of FIG. 3), the Z° angle ofthe cutout of the crown stopper 10 which is defined between end faces 10aand 10 b, the Y° angle of the cutout of the holding stopper 11 which isdefined between end faces 11 a and 11 b, and the X° angle of the endportion 12 c of the rotation-stopping arm 12 are selected to meet therelationship:

Z>Y>X.

Thus, the cutout of the holding stopper 11 lies above the cutout of thecrown stopper 10 in such a manner that an edge portion of the holdingstopper 11 partially covers the cutout of the crown stopper 10, as shownin FIG. 4. These cutouts are positioned above the respective outputgears 9 a to 9 d. The height at which each of the stoppers 10 and 11 isfixed (the vertical height in FIG. 2) is selected so that the followingtwo states are possible:

1) When the end portion 12 c of the rotation-stopping arm 12 movesupward in interlocked relation to the pulling operation of the plunger16, the end portion 12 c of the rotation-stopping arm 12 does not engagewith any of the cutouts of the stoppers 10 and 11 (refer to FIGS. 6(a),6(b) and 6(c) which will be referred to later); and

2) If the plunger 16 is not performing a pulling operation, theprojection 15 e of the arm 15 urges the rotation-stopping arm 12downward to locate the end portion 12 c of the rotation-stopping arm 12at a height flush with the end faces 10 a and 10 b which define thecutout of the crown stopper 10 (refer to the state of FIG. 2).

In the case of the state 1) (the state shown in FIGS. 6(a), 6(b) and6(c) which will be referred to later), the rotating arm 5, the partssecured thereto (the rotation-stopping arm 12, the planetary shaft 8 a,the pulse disc 14, etc.) and the planetary gear 7 can rotate about thebearing 4 freely and integrally. The planetary gear 7 freely revolveswith the rotation of the output shaft 3 and hence with the rotation ofthe sun gear 6. During this time, the planetary gear 7 revolves whileselectively meshing with the circumferentially arranged output gears 9 ato 9 d.

In the case of the state 2), the horizontal rotation of therotation-stopping arm 12 is limited by the end faces 10 a and 10 b ofthe crown stopper 10. The rotating arm 5 which is integral with therotation-stopping arm 12 is inhibited from rotating, thereby stoppingthe revolution of the planetary gear 7. This state corresponds to thestate shown in FIGS. 2, 3 and 9(a), 9(b), 9(c).

The planetary gear 7 whose revolution has been limited in theabove-described manner is allowed to rotate on its axis at thatposition, that is, at a position corresponding to any one of the cutoutsof the stoppers 10 and 11. During this time, the planetary gear 7 is inmesh with any one of the output gears 9 a to 9 d and constitutes a geartrain, whereby the planetary gear 7 can transmit the rotation of the sungear 6 to the output gear in mesh. Whether the direction of rotation ofthe sun gear 6 is right-handed or left-handed, the planetary gear 7 cantransmit the rotation to the output gear in mesh.

The crown stopper 10 has an erected portion 10 c. The erected portion 10c inhibits the planetary gear 7 from freely rotating through an anglenot less than 360°, and allows the planetary gear 7 to make only oneleft-handed or right-handed revolution. Specifically, the end portion 12c of the rotation-stopping arm 12 is positioned above the crown stopper10 and the holding stopper 11 by the pulling operation of the plunger 16(the state of FIGS. 6(a), 6(b) and 6(c) which will be referred to), andthe planetary gear 7 is placed in a freely revolvable state. However,since the erected portion 10 c serves as a stopper for the end portion12 c of the rotation-stopping arm 12, the free revolution of theplanetary gear 7 is inhibited. The state of the free revolution beinginhibited is shown in FIGS. 5(a), 5(b), 5(c) and 7(a), 7(b), 7(c). Atthis position, since the erected portion 10 c works as a stopper and theplanetary gear 7 initiates rotation on its axis, the erected portion 10c is provided at a location where the planetary gear 7 does not meshwith any of the output gears 9 a to 9 d.

As the planetary gear 7 revolves, the rotating arm 5 and the planetaryshaft 8 a rotate about the sun gear 6. The pulse disc 14 which rotatesintegrally with the rotating arm 5 and the planetary shaft 8 a rotatesin interlocked relation to the revolution of the planetary gear 7. Thepulse disc 14 has a circumferentially alternate pattern of bright anddark segments, and a bright or dark signal (pulse) derived from a brightor dark segment is detected by a photocoupler 17 and a pulse signaldetecting circuit 22 which will be described later (refer to FIG. 17).The pattern of the bright and dark segments has a configuration whichmakes it possible to detect from the output of the photocoupler 17 (andthe pulse signal detecting circuit 22 which will be described later) theperiod in which the planetary gear 7 is in mesh with any one of theoutput gears 9 a to 9 d or the period in which the planetary gear 7 isin mesh with none of the output gears 9 a to 9 d.

In the first embodiment, each bright pattern segment 14 e is formed sothat a “bright” signal can be produced when the planetary gear 7 and anyone of the output gears 9 a to 9 d are in mesh, and each dark patternsegment 14 d is formed so that a “dark” signal can be produced when theplanetary gear 7 is in mesh with none of the output gears 9 a to 9 d(refer to FIG. 1). In the first embodiment, since the output gears 9 ato 9 d are four in number, the bright pattern segments 14 e are providedin four positions. In this construction, the position of the planetarygear 7 which is revolving can be identified from the output of thephotocoupler 17 (and the output of the pulse signal detecting circuit 22which will be described later).

The operation of the power dividing device having the above-describedconstruction will be described below.

It is assumed here that, as shown in FIG. 5(a), the clockwise rotationof the sun gear 6 is indicated by “Rv” and the counterclockwiserotation, by “Fw”. The direction of rotation of the sun gear 6 is thesame as the direction of revolution of the planetary gear 7, thedirection of rotation of each of the output gears 9 a to 9 d, thedirection of rotation of the rotating arm 5 and the direction ofrotation of the rotation-stopping arm 12 and, in addition, the directionof rotation of the motor 1. It is also assumed that the regions aroundwhich the planetary gear 7 revolves are indicated by “X” and the numbers{circle around (1)} to {circle around (8)}, respectively. Each of theregions also indicates the position of the end portion 12 c of therotation-stopping arm 12 with respect to the crown stopper 10. Theregion X is a region including an initial position 10 d in which theplanetary gear 7 does not mesh with any of the output gears 9 a to 9 d.

The regions {circle around (1)}, {circle around (3)}, {circle around(5)} and {circle around (7)} are regions in which the planetary gear 7meshes with the output gears 9 d to 9 a, respectively. These regions(positions) are identified by a control circuit 24 which will bedescribed later (refer to FIG. 17) on the basis of a result obtained bydetecting the number of transitions between “bright” and “dark” pulsesfrom the output of the photocoupler 17. More specifically, as theplanetary gear 7 revolves in the “Rv” direction in the order of {circlearound (8)}→{circle around (7)}→{circle around (6)}→. . . (in the orderof FIG. (5)→FIG. 6(a)→FIG. 7(a)), the bright and dark pattern segmentsof the pulse disc 14 are sequentially detected, and “bright” and “dark”signals such as those shown in FIG. 11 are outputted from thephotocoupler 17. Accordingly, if a “bright” signal is outputted, thisindicates that the planetary gear 7 is positioned in any one of theregions {circle around (7)}, {circle around (5)}, {circle around (3)}and {circle around (1)} and is in mesh with any one of the output gears9 a to 9 d. If a “dark” signal is outputted, this indicates that theplanetary gear 7 is positioned in any one of the regions {circle around(2)}, {circle around (4)}, {circle around (6)} and {circle around (8)}and is in mesh with none of the output gears 9 a to 9 d.

As described previously, since the erected portion 10 c of the crownstopper 10 comes into abutment with the end portion 12 c of therotation-stopping arm 12, the planetary gear 7 is inhibited fromrevolving from the region X to the region {circle around (8)} or fromthe region {circle around (8)} to the region X.

When the plunger 16 is energized to make the planetary gear 7 revolve,the planetary gear 7 initiates revolution. Then, if the energization ofthe plunger 16 is stopped when the gear 7 is positioned in any one ofthe regions {circle around (2)}, {circle around (4)}, {circle around(6)} and {circle around (8)}, the end portion 12 c of therotation-stopping arm 12 stops in the state of riding on the holdingstopper 11 (the state shown in FIGS. 8(a), 8(b) and 8(c)).

In this state, parts which rotate about the bearing 4, such as therotating arm 5, the rotation-stopping arm 12, the planetary gear 7 andthe pulse disc 14, are placed in instable positions. More specifically,the end portion 12 c of the rotation-stopping arm 12 may slide on theholding stopper 11 and drop into the cutout within any one of theregions {circle around (1)}, {circle around (3)}, {circle around (5)}and {circle around (7)} owing to vibrations or the like (the state shownin FIGS. 9(a), 9(b) and 9(c)). Thus, the planetary gear 7 will mesh withthe one of the output gears 9 a to 9 d with which it should not mesh,owing to vibrations or the like. In contrast, if the energization of theplunger 16 is stopped and the end portion 12 c of the rotation-stoppingarm 12 enters the region X, particularly the area of the initialposition 10 d, the end portion 12 c enters the area between the erectedportion 10 c and the end face 10 e and the planetary gear 7 becomesunable to revolve, as in the other regions {circle around (2)}, {circlearound (4)}, {circle around (6)} and {circle around (8)} of the crownstopper 10 (the state of FIG. 7(a)). Since there is none of the outputgears 9 a to 9 d, no power is transmitted even if the motor 1 operates.Accordingly, the region X (the initial position 10 d) may be regarded asa “neutral position”.

Since the “initial position” in which the planetary gear 7 is in meshwith none of the output gears 9 a to 9 d and is allowed to rotate on itsaxis without revolution is provided in the above-described manner, thedevice can be placed in a stable stop state.

The basic operation of the power dividing device according to the-firstembodiment is that “the planetary gear 7 which revolves around the sungear 6 stops revolving at an arbitrary one of the output gears 9 a to 9d which surround the planetary gear 7 circumferentially, and transmits,while rotating only, the power of the sun gear 6 to the arbitrary one ofthe output gears 9 a to 9 d”. The outline of such a sequential operationwill be described below.

First when the plunger 16 is energized, the rotation-stopping arm 12 isremoved from any one of the cutouts of the crown stopper 10 and theplanetary gear 7 is placed in a freely revolvable state. Then, the motor1 is activated to make the planetary gear 7 revolve in an arbitrarydirection. At this time, the pulse disc 14 is also made to rotate. Then,the amount of rotation of the pulse disc 14 is detected from the outputof the photocoupler 17, that is, the number of “bright” and “dark”pulses generated by the rotation of the pulse disc 14 is counted,whereby the region where the planetary gear 7 is positioned is detectedfrom among the regions X to {circle around (8)}. When it is detectedthat the planetary gear 7 has revolved up to the desired one of theoutput gears 9 a to 9 d to which power is to be transmitted theenergization of the plunger 16 is turned off and the end portion 12 c ofthe rotation-stopping arm 12 is made to enter the associated cutout ofthe crown stopper 10, thereby limiting the revolution of the planetarygear 7. Then, the rotation of the motor 1 is transmitted to thearbitrary one of the output gears 9 a to 9 d, whereby the power istransmitted.

As will be described in detail in connection with “entrance operation”and “exit operation” both of which will be described later, since thepulse disc 14 rotates with the revolution of the planetary gear 7, theposition of the planetary gear 7 which is revolving is identified fromthe output of the photocoupler 17 (the number of transitions between“bright” and “dark” pulses). However, in the aforesaid operational stepin which “when it is detected that the planetary gear 7 has revolved upto the desired one of the output gears 9 a to 9 d to which power is tobe transmitted, the energization of the plunger 16 is turned off”, it isnecessary to determine how the planetary gear 7 is meshed with thedesired one of the output gears 9 a to 9 d or where the end portion 12 cof the rotation-stopping arm 12 is positioned with respect to the crownstopper 10 and the holding stopper 11. Such a decision is made on thebasis of the detection of the falling edge of a pulse changing from its“bright” level to its “dark” level or the rising edge of a pulsechanging from the “dark” level to the “bright” level. In other words, byusing the pulse disc 14 and the photocoupler 17, it is possible not onlyto count the number of transitions between the “bright” and “dark”pulses but also to detect the rising and falling edges of each of the“bright” and “dark” pulses. In this arrangement, control of the motor 1and the plunger 16 is performed to implement fine operational controlfor “entrance” and “exit” of the rotation-stopping arm 12 into and fromany one of the cutout of the crown stopper 10.

The “initial positioning” operation will be described below.

To detect the region where the planetary gear 7 is revolving from amongthe regions X to {circle around (8)}, the pulse disc 14 and thephotocoupler 17 are used. However, since there are only two kinds ofsignals corresponding to “brightness” and “darkness” as shown in FIG.11, it is only possible to detect how far the planetary gear 7 hasrevolved since detection was started, that is, the number of transitionsindicated by the count of pulse signals. For this reason, immediatelyafter the present device has been activated, it is impossible to detecta position (initial state) where the planetary gear 7 is located at thattime. Accordingly, control is provided so that the operation of“necessarily finding the “initial position 10 d” in whatever state thedevice may be placed” can be performed when the present device isactivated. Such an operation will be hereinafter referred to as the“initial positioning” operation.

In operation, first, the plunger 16 is energized to place the planetarygear 7 in a freely revolvable state. Then, the planetary gear 7 is madeto revolve unconditionally in the “Fw” direction until the end portion12 c comes into abutment with the erected portion 10 c, that is, up tothe region {circle around (8)}. Subsequently, while pulse transitionsare being counted, the planetary gear 7 is made to revolve in the “Rv”direction until the end portion 12 c enters the “initial position 10 d”.The energization of the plunger 16 and the motor 1 is stopped and theplanetary gear 7 is placed in a stable stop state at that position.Since this state indicates that the end portion 12 c is located in theregion X, more specifically, the initial position 10 d of the crownstopper 10, it is possible to detect where the planetary gear 7 islocated from among the regions X to {circle around (8)}, on the basis ofthe initial position 10 d by using the “bright” and “dark” signalsdetected by the combination of the photocoupler 17 and the pulse disc14.

What is important in the aforesaid operational step is that the erectedportion 10 c of the crown stopper 10 and the end portion 12 c of therotation-stopping arm 12, which cooperate to serve as an abutmentportion for limiting a right-handed or left-handed revolution of theplanetary gear 7, have a positional relationship in which the planetarygear 7 is in mesh with none of the output gears 9 a to 9 d, as describedabove, (the states shown in FIGS. 5(a) and 7(a)).

The above-described “initial positioning” operation is needed in anumber of cases, for example:

when it is impossible to determine in which region of the regions X to{circle around (8)} the planetary gear 7 is located at the time ofactivation of the present device.

when “erroneous selection of an element to which power is to betransmitted” takes place, that is, when there is a discrepancy betweenthe position of the planetary gear 7 which is memorized in the controlcircuit which will be described later and the position where theplanetary gear 7 is actually located.

For the above-noted and other reasons, since the original position ofthe planetary gear 7 is not known, even if the pulse disc 14 and thephotocoupler 17 are used to perform position detection based on relativepulse transitions of pulses for the purpose of detecting the position ofthe planetary gear 7, the position thus detected has no substantialmeaning.

For this reason, in the first half of the “initial positioning”operation, after the energization of the plunger 16, the motor 1 isdriven in the “Fw” direction rotation without detection of pulsetransitions, thereby causing the planetary gear 7 to revolve up to theregion {circle around (8)}, that is, until the end portion 12 c comesinto abutment with the erected portion 10 c (the state of FIG. 5(a).During this time, the motor 1 is driven to rotate only during the timeperiod required for the planetary gear 7 to make one revolution from{circle around (8)} to X or vice versa (500 msec in this example), andthe motor 1 is merely driven to rotate unconditionally in the “Fw”direction, thereby bringing the end portion 12 c of therotation-stopping arm 12 into abutment with the erected portion 10 c ofthe crown stopper 10. However, as will be described later in connectionwith the “exit operation”, there are some conditions under which theplanetary gear 7 is unable to freely revolve if the planetary gear 7initially performs no revolution in the “Rv” direction. Accordingly, insome cases, the motor 1 is first driven to rotate in the “Rv” directionduring the above-described predetermined time period and makes theplanetary gear 7 to revolve in the “Rv” direction up to the position ofX (the state of FIG. 7(a)), and then the planetary gear 7 is made torevolve in the “Fw” direction, thereby bringing the end portion 12 cinto abutment with the erected portion 10 c in the region {circle around(8)}.

When such an abutment state is reached, the planetary gear 7 may beconsidered to be located in the region {circle around (8)}. Subsequentlyto the abutment state, the position of the planetary gear 7 duringrevolution may be determined while pulse transitions between “bright”and “dark” are being detected through the pulse disc 14 and thephotocoupler 17 in the known manner.

Accordingly, in the second half of the “initial positioning” operation,the motor 1 is driven to rotate in the “Rv” direction, thereby causingthe planetary gear 7 to revolve from the region {circle around (8)} tothe region X while pulse transitions are being detected. If theplanetary gear 7 is correctly positioned in the region {circle around(8)} in the first half of the “initial positioning” operation and if theplanetary gear 7 can revolve from the region {circle around (8)} to theregion X, it follows that a pulse transition from the “bright” level tothe “dark” level and a pulse transition from the “dark” level to the“bright” level are detected four times each.

In the above-described manner, a limiting member (the erected portion 10c) which places the planetary gear 7 in the state of being meshed withnone of the output gears 9 a to 9 d is provided in the abutment positionfor limiting the revolution of the planetary gear 7, and this positionis rendered the neutral position in which the planetary gear 7 isallowed to rotate without revolution. Accordingly, when the planetarygear 7 is to be revolved, particularly if it is impossible to detect theposition of the planetary gear 7 during revolution, the planetary gear 7can be made to rotate on its axis in mesh with none of the output gears9 a to 9 d even if the motor 1 is driven to rotate during apredetermined time period. Accordingly, it is possible to find theneutral position (particularly, the initial position 10 d of the crownstopper 10) which serves as the abutment position without the risk ofunwanted transmission of power.

The advantages of the “initial positioning” operation will be describedbelow.

The “initial positioning” operation also includes the operation ofchecking whether the planetary gear 7 can reliably revolve up to each ofthe regions in the order of {circle around (8)}→{circle around(7)}→{circle around (6)}→{circle around (5)}→{circle around (4)}→{circlearound (3)}→{circle around (2)}→{circle around (1)}→X. Accordingly, the“initial positioning” operation has the function of checking whether thepresent device can operate correctly. More specifically, if theplanetary gear 7 can make one revolution (in this example, onerevolution in the “Rv” direction), a pulse transition from the “bright”level to the “dark” level and that from the “dark” level to the “bright”level are detected four times each, as shown in FIG. 11. If such fourpulse transitions are not correctly detected, this indicates that theplanetary gear 7 has not correctly revolved and a mechanical failure hasoccurred in the power dividing device.

Referring to FIG. 19, from Step #10 “COUNT PULSE” to Step #12, pulsecounting is performed to detect whether eight pulse transitions between“bright” and “dark” have occurred. Through this pulse counting, it ispossible to check the operation of the present device.

In the above-described manner, in the present device which is adapted todetect the position of the planetary gear 7 during revolution on thebasis of the number of relative transitions of a pulse signal or thelike, when the position of the planetary gear 7 is to be found by “theinitial positioning”, the motor 1 is energized to rotate unconditionallyin one direction during a predetermined time period to perform theabutment operation of bringing the end portion 12 c into abutment withthe erected portion 10 c. Thereafter, when the motor 1 is energized torotate in the reverse direction, whether a prescribed number of pulsesignals have been outputted is detected, whereby it is also possible tocheck the operation of the present device at the same time.

There is another case where the “initial positioning” operation isneeded, in addition to the time of activation of the present device atwhich the “initial positioning” operation is performed (forsimultaneously checking whether the planetary gear 7 can reliablyrevolve around the regions X to {circle around (8)} and up to each ofthem). As will be described in detail in connection with FIGS. 17 and19, mechanisms 25 a to 25 d for power transmission (refer to FIG. 17)are provided with circuit parts for generating drive signals 26 a to 26d (refer to FIG. 17) for feedback of their respective operations.Accordingly, it is possible to again perform selection of an element towhich power dividing is to be directed, by executing the “initialpositioning” operation, even if such an element is erroneously selected,for example, in a case where while any one of the output gears 9 a to 9d is transmitting power to the associated one of the mechanisms 25 a to25 d, the corresponding drive signal 26 a, 26 b, 26 c or 26 d is nottransmitted, or in a case where the drive signal 26 a, 26 b, 26 c or 26d is transmitted from the one of the mechanisms 25 a to 25 d to whichpower need not to be transmitted.

As is apparent from the above description, the reason why “initialpositioning” operation is needed is to detect the position of theplanetary gear 7 during revolution on the basis of the relative pulsetransitions obtained from the combination of the photocoupler 17 and thepulse disc 14, as described previously. If the present device isprovided with a mechanism capable of detecting the position of theplanetary gear 7 during revolution as an absolute position, theabove-described “initial positioning” operation is not needed. However,it will be necessary to increase the complexity and size of the presentdevice.

When the “initial positioning” operation is completed, the planetarygear 7 is reliably positioned in the region X, more specifically, theregion of the initial position 10 d of the crown stopper 10.Accordingly, it is possible to implement a reliable power dividingoperation by determining which of the output gears 9 a to 9 d and theplanetary gear 7 are in mesh with each other while “bright” and “dark”signals are being detected through the combination of the photocoupler17 and the pulse disc 14 during the revolution of the planetary gear 7from that position. For this reason, in the present device adapted todetermine which of the output gears 9 a to 9 d and the planetary gear 7are in mesh with each other on the basis of only relative transitionsbetween the “bright” and “dark” signals, if the “initial positioning”operation is performed for each power dividing operation and reliableselection of an element to which power is to be transmitted is carriedout, the reliability of the device will improve. However, if the“initial positioning” operation is performed each time the element towhich power is to be transmitted is changed, it will require atime-consuming sequence of operations since the “initial positioning”operation itself is not an actual power transmission operation but aswitching operation.

Accordingly, if the “initial positioning” operation is performed asactively as possible in the case of an operation which is not seriouslyaffected by the length of an operating time period, except for anoperation such as the operation of continuously transmitting power tothe output gears 9 a to 9 d, it is possible to improve the reliabilityof the device.

As described above, in the device for performing position detection onthe basis of the number of relative transitions, particularly in thedevice whose operation is set so that the “initial positioning”operation is carried out, it is possible to improve the reliability ofthe device by actively performing the “initial positioning” operationeach time the element to which power is to be transmitted is changed, inan operational portion the entire control process of which is notimpaired by the “initial positioning” operation.

In practice, the “initial positioning” operation is performed in Step#91 in the main operation of a camera which will be described later(refer to FIG. 18). In the flowchart of FIG. 18, the “initialpositioning” operation is performed immediately before a rewindingoperation. Switching to the rewinding operation is an operation whichtakes a certain time period, and since insertion of a short time periodin this step offers no substantial problem, the “initial positioning”operation is performed in Step #91. In automatic loading as well, the“initial positioning” operation is performed before the completion ofthe automatic loading (Steps #141 and #147 of FIG. 25). Since theautomatic loading as well as the rewinding operation takes a certaintime period, this “initial positioning” operation is performed toimprove the reliability of the control of the entire device describedabove.

The “initial positioning” operation in a camera provided with the deviceaccording to the first embodiment will be described later with referenceto FIG. 19.

As described previously in connection with the basic operation of thepower dividing device, the plunger 16 is turned on or off to cause theend portion 12 c of the rotation-stopping arm 12 to enter into or exitfrom (disengage from) any one of the cutouts of the crown stopper 10.The motor 1 and the plunger 16 perform fine operations, respectively, toassist in the operation of causing the end portion 12 c to enter into orexit from the cutout of the crown stopper 10, in response to the“bright” and “dark” signals for providing on-off timing which areobtained from the pulse disc 14. The “entrance operation” and the “exitoperation” will be described below.

First, the “exit operation” will be described below.

The holding stopper 11 which has a shape similar to that of the crownstopper 10 is disposed on the crown stopper 10. Although the shape ofthe holding stopper 11 resembles that of the crown stopper 10, asdescribed previously in connection with FIG. 4, the angle of each of thecutout of the holding stopper 11 is selected to be:

X>Y>X.

This angle is the requirement necessary for implementation of the “exitoperation”.

FIG. 12(a) is a model diagram of the first embodiment, taken in thedirection of the arrow L shown in FIG. 3 or 8(a), and the obverse sideof the sheet of each of FIGS. 3 and 8(a) corresponds to the top side ofFIG. 12(a). FIG. 12(a) represents the relationships between the crownstopper 10, the holding stopper 11 and the end portion 12 c of therotation-stopping arm 12, and dashed lines represent the loci of motionsoccurring when the end portion 12 c of the rotation-stopping arm 12engages with or disengages from the crown stopper 10 or the holdingstopper 11. The dashed lines also represent signals obtainable when thephotocoupler 17 detects the bright pattern segments 14 e or the darkpattern segments 14 d of the pulse disc 14 which rotates in interlockedrelation to the rotation of each of the rotation-stopping arm 12, therotating arm 5, the planetary gear 7 and so on. The thick dashed linescorrespond to the “bright” signals and indicate that the planetary gear7 is located in any one of the regions {circle around (1)}, {circlearound (3)}, {circle around (5)} and {circle around (7)}, while the thindashed lines correspond to the “dark” signals and indicate that theplanetary gear 7 is located in any one of the regions X, {circle around(2)}, {circle around (4)}, {circle around (6)} and {circle around (8)}.Each of FIGS. 13(a) and 13(b) is a timing chart showing the operationaltiming of the present device during the execution of the “exitoperation”, and shows the direction of rotation of the motor 1, thetiming of the pulling operation of the plunger 16, and the transitionbetween the “bright” and “dark” signals which is obtained when thephotocoupler 17 detects the pattern of the pulse disc 14. FIGS. 13(a)and 13(b) correspond to FIGS. 12(a) and 12(b), respectively.

FIGS. 9(a), 9(b) and 9(c) show the state wherein the planetary gear 7 ispositioned in the region {circle around (5)} while transmitting thepower conducted through the output gear 9 b which is rotating in the“Fw” direction (refer to FIG. 9(b)). During this time, the revolvingforce of the planetary gear 7 in the “Fw” direction is cancelled by therotation-stopping arm 12 which is engaged with the cutout (the end face10 a) of the crown stopper 10. The operation of stopping the powertransmission through the output gear 9 b and causing the planetary gear7 to revolve from the output gear 9 b to another output gear (9 a, 9 cor 9 d) will be described below. First, energization of the plunger 16is started to disengage the end portion 12 c of the rotation-stoppingarm 12 from the cutout of the crown stopper 10. However, the end portion12 c of the rotation-stopping arm 12 may not move up owing to frictionbetween the end portion 12 c and each face of the crown stopper 10 whichdefines the cutout (the end face 10 a). This phenomenon will occur evenif the rotation of the planetary gear 7 in the “Rv” direction, that is,the rotation of the motor 1 in the “Fw” direction, is continued orstopped after the completion of the pulling operation of the plunger 16.

In other words, if the planetary gear 7 continues rotating in the “Rv”direction, the end portion 12 c of the rotation-stopping arm 12 and thecutout (the end face 10 a) of the crown stopper 10 remain in abutmentwith each other. Even if the rotation of the planetary gear 7, that is,the rotation of the motor 1, is stopped, the end portion 12 c of therotation-stopping arm 12 remains urged against the end face 10 a of thecutout of the crown stopper 10 owing to the backlash of the gear train.

For this reason, the following process is needed:

After the completion of the pulling operation of the plunger 16, themotor 1 is reversed in the “Rv” direction to remove the backlash,thereby eliminating the friction between the end portion 12 c of therotation-stopping arm 12 and the cutout (the end face 10 a) of the crownstopper 10. If the friction is eliminated, the end portion 12 c is madeto disengage from the cutout (the end face 10 a) of the crown stopper10. However, the force of the friction is not always uniform inmagnitude, and if the spring balance between the torsion spring 15 c forthe arm 15 and the pulling force of the plunger 16 is taken intoaccount, it is undesirable that the strength of the torsion spring 13 bfor moving up the rotation-stopping arm 12 be selected to beunconditionally large. The holding stopper 11 is employed as acountermeasure for solving the above-described problem. Morespecifically, even if the arm 15 moves up from the rotation-stopping arm12 and the projection 15 e stops pressing it down, the end portion 12 cof the rotation-stopping arm 12 is held in engagement with the holdingstopper 11 until the end portion 12 c completely comes out of contactwith the cutout (the end face 10 a) and the friction disappears (referto FIGS. 9(a), 10(a) and 10(b)).

The above-described operation will be described in more detail withreference to FIG. 12(a).

As described previously, FIG. 12(a) is a view taken in the direction ofthe arrow L of FIG. 8(a). As described above, to eliminate the influenceof friction or the like, it is necessary to bring the end portion 12 cof the rotation-stopping arm 12 out of engagement with the crown stopper10 after the planetary gear 7 starts revolving in the “Rv” direction. Inother words, it is absolutely necessary to hold the end portion 12 c inengagement with the crown stopper 10 until the planetary gear 7 startsrevolving in the “Rv” direction. The holding stopper 11 performs thefunction of holding the end portion 12 c in engagement with the crownstopper 10 until the start of the revolution of the planetary gear 7 inthe “Rv” direction. To fulfill such a function, it is essential to meetthe previously-described relationship between the angles (Z>Y>X).Incidentally, in FIGS. 12(a) and 12(b), each of the angles correspondsto a lateral width.

The present device is not provided with a sensor for detecting whetherthe end portion 12 c of the rotation-stopping arm 12 has disengaged,i.e., moved up, from the holding stopper 11 and the crown stopper 10. Inthe present device, the function of such a sensor is realized byutilizing “bright” and “dark” signals detected from the pulse disc 14.

Referring to FIGS. 12(a) and 13(a), if the crown stopper 10 is in meshwith the rotation-stopping arm 12 as shown in, for example, FIG. 12(a),a “bright” signal (a signal indicating that the end portion 12 c ispositioned in the region {circle around (5)}) is detected. When acertain time period has elapsed after the completion of the pullingoperation of the plunger 16, the motor 1 is driven to rotate in the “Rv”direction. If the rotation-stopping arm 12 passes through the spacebetween the end faces 11 a and 11 b of the holding stopper 11 anddisengages from the cutout of the crown stopper 10 as shown by thedashed loci of FIG. 12(a), the rotating arm 5 starts rotating in the“Rv” direction, so that a “dark” signal (a signal indicating that theend portion 12 c is positioned in the region {circle around (4)}) isdetected as shown at 201 in FIG. 12(a) and it is indirectly indicatedthat the end portion 12 c has disengaged from the crown stopper 10.After the detection of the signal, the motor 1 is driven so that theplanetary gear 7 is made to revolve in the next desired direction, thatis, so that the planetary 7 is made to revolve toward the next one ofthe output gears 9 a, 9 c and 9 d to which power is to be transmitted.However, if, as shown in, for example, FIG. 12(b), the direction inwhich the sun gear 6 is made to rotate to eliminate the friction betweenthe crown stopper 10 and the rotation-stopping arm 12 is the same as thedirection in which the planetary gear 7 is made to revolve after the endportion 12 c has disengaged from the holding stopper 11, the motor 1 maybe continuously driven to rotate in the same direction so that a seriesof operations may continue.

As shown in FIGS. 13(a) and 13(b), when a certain time period 207elapses after the start of the pulling operation of the plunger 16, therotation of the motor 1 is started. If the time period 207 is too short,the planetary gear 7 may start revolving before the projection 15 e ofthe arm 15 moves up, depending on the length of the pulling time of theplunger 16. In this case, the end portion 12 c of the rotation-stoppingarm 12 may only travel from the end face 11 a to the end face 11 b ofthe cutout of the holding stopper 11, and may not disengage from thecrown stopper 10. To assure a time margin for preventing occurrence ofsuch disengagement, the time lag shown at 207 is provided between thestart of the pulling operation of the plunger 16 and the start ofrotation of the motor 1.

The foregoing is a description of the “exit operation” which isperformed since the transmission of power to a certain output gear (inthis example, the output gear 9 b) is completed until the planetary gear7 starts switching to the next output gear 9 a, 9 c or 9 d.

Since the holding stopper 11 is provided in the above-described manner,it is possible to reliably perform the switching operation following thepower transmission without the need to strictly control various factorssuch as the spring balance in the present device, the characteristics ofthe plunger 16, the variations of the frictional force between the crownstopper 10 and the rotation-stopping arm 12 due to the differencebetween the shapes of actual parts used as the crown stopper 10 or therotation-stopping arm 12, and the amount of backlash.

The “entrance operation” of stopping the revolution of the planetarygear 7 at the desired output gear 9 a, 9 c or 9 d and startingtransmission of power will be described below with reference to FIGS.14(a), 14(b) and FIGS. 15(a), 15(b). The relation between FIGS. 14(a),14(b) and FIGS. 15(a), 15(b) is similar to that between FIGS. 12(a),12(b) and FIGS. 13(a), 13(b).

Although the holding stopper 11 itself is not needed in the “entranceoperation”, the holding stopper 11 which is positioned above the crownstopper 10 does not hinder the “entrance operation”.

For example, when the planetary gear 7 is to be stopped in the region{circle around (5)} as shown in FIGS. 9(a), 9(b) and 9(c) during therevolution in the “Fw” direction, the planetary gear 7 is made torevolve from the region {circle around (4)} in the same direction. Then,the revolution of the planetary gear 7 is stopped by the cooperationbetween the crown stopper 10 and the rotation-stopping arm 12 bystopping the pulling operation of the plunger 16. Thus, transmission ofpower to the output gear 8 b is started. FIGS. 14(a) and 14(b) showdifferent processes of the aforesaid operation. The difference betweenFIGS. 14(a) and 14(b) resides in the direction in which the output gear9 b positioned in the region {circle around (5)} is to be rotated. FIG.14(a) shows the manner in which the output gear 9 b is made to rotate inthe “Rv” direction via the planetary gear 7, and at this time the endportion 12 c of the rotation-stopping arm 12 is stopped by engagementwith the end face 10 b in the cutout of the crown stopper 10. FIG. 14(b)shows the manner in which the output gear 9 b is made to rotate in the“Fw” direction, and at this time the end portion 12 c is stopped byengagement with the end face 10 a in the cutout of the crown stopper 10.As is apparent from the above description, as in the case of the “exitoperation”, two ways of entrance are prepared in the “entranceoperation”. The reasons are as follows:

1) It is necessary to make the direction of revolution of the planetarygear 7 the same as that of rotation of the next one of the output gears9 a, 9 b, 9 c and 9 d to which power is to be transmitted; and

2) A device is not provided which directly detects whether the endportion 12 c of the rotation-stopping arm 12 has entered the cutout ofthe crown stopper 10.

The “entrance operation” will be described below with reference to FIGS.14(a) and 15(a).

When the planetary gear 7 is made to revolve from the region {circlearound (4)} in the “Fw” direction with the movable yoke 16 a of theplunger 16 pulled, the planetary gear 7 enters the region {circle around(5)} during the detection of a “dark” signal 203 indicative of theregion {circle around (4)}, and a “bright” signal 208 indicative of theregion {circle around (5)} is detected. If the pulling operation of theplunger 16 is continued to make the planetary gear 7 revolve further inthe “Fw” direction, the planetary gear 7 moves out of the region {circlearound (5)} and a “dark” signal 202 indicative of the region {circlearound (6)} is detected. In response to the “dark” signal 202, the motor1 is driven to rotate in the “Rv” direction, that is, the revolution ofthe planetary gear 7 in the “Rv” direction is started. Then, since a“bright” signal 204 indicating that the planetary gear 7 has entered theregion {circle around (5)} is detected, the pulling operation of theplunger 16 is stopped in response to the “bright” signal 204. At thispoint in time, the end portion 12 c of the rotation-stopping arm 12 ispositioned on the holding stopper 11 (the state shown in FIGS. 8(a),8(b) and 8(c)). During this time, the rotation-stopping arm 12 and theholding stopper 11 are in face-to-face contact with each other (in theposition shown at 205) and the rotation-stopping arm 12 rotates infrictional contact with the holding stopper 11. If the frictional forceis larger than the revolving force of the planetary gear 7, the rotatingarm 5, the rotation-stopping arm 12 and so on may stop rotating. Forthis reason, timing to stop the pulling operation of the plunger 16,that is to say, the angular extent of opening of each bright patternsegment 14 e of the pulse disc 14, that is, the width of each of theregions {circle around (1)}, {circle around (3)}, {circle around (5)}and {circle around (7)}, must be detected in the following manner:

“If the planetary gear 7 is positioned at one end of the region {circlearound (5)} as shown in FIGS. 6(a), 6(b) and 6(c), the planetary gear 7is necessarily in mesh with the output gear 9 b”.

In the above-described arrangement, if the planetary gear 7 ispositioned in the region {circle around (5)}, the planetary gear 7revolves while rotating not by a revolving force generated by the spring8 b but by engagement with the sun gear 6 or the output gear 9 b. Inthis manner, the planetary gear 7 revolves in the “Rv” directionirrespective of the friction due to the face-to-face contact between therotation-stopping arm 12 and the holding stopper 11. Thus, the endportion 12 c of the rotation-stopping arm 12 reliably comes out ofcontact with the holding stopper 11, passes through the cutout of theexit stopper 11 (the space defined between the end faces 11 a and 11 b),and engages with the end face 10 b in the cutout of the crown stopper10. At the same time that the revolution of the planetary gear 7 in the“Rv” direction is stopped, only the rotation of the planetary gear 7 isstarted, whereby the output gear 9 b starts rotating. In theabove-described manner, if the direction of revolution of the planetarygear 7 (the “Rv” direction in FIG. 14(a)) is made the same as thedesired direction of rotation of the output gear 9 b, the motor 1 may bedriven in the same direction during the period from the time the pullingoperation of the plunger 16 is stopped until the time the revolution ofthe planetary gear 7 is stopped by the crown stopper 10 and the desiredone of the output gears 9 a to 9 d starts rotating. If the signal 204indicative of the transition from the “bright” level to the “dark” levelwhen the planetary gear 7 moves from the region {circle around (6)} tothe region {circle around (5)} is detected in the above-describedmanner, it is possible to detect indirectly but reliably whether the endportion 12 c of the rotation-stopping arm 12 has entered the cutout ofthe crown stopper 10.

FIGS. 14(b) and 15(b) are views showing a case where the direction ofrevolution of the planetary gear 7 is the same as the direction ofrotation of the desired one of the output gears 9 a to 9 d. In thiscase, an operation is performed which is substantially the same as thatperformed subsequently to the detection of a signal indicative of thetransition of the signal 204 from the “dark” level to the “bright”level, which signal 204 indicates that the planetary gear 7 has meshedwith the one of the output gears 9 a to 9 d to which power istransmitted. The signal indicative of the transition from the “dark”level to the “bright” level is a signal 204′ in FIGS. 14(b) and 15(b).

The foregoing is a description of the “entrance operation”.

As described above, if the direction of power transmission (rotation) ofthe desired one of the output gears 9 a to 9 d to which power dividingis to be directed is made the same as the revolving direction of theplanetary gear 7, there is no need to change the direction of rotationof the motor 1. Accordingly, the desired one of the output gears 9 a to9 d does not rotate in the reverse direction, and the desired mechanismto which the power is to be transmitted does not operate in the reversedirection. In addition, it is possible to reliably select the desiredone to which the power dividing is to be directed.

FIG. 17 is a schematic view showing the essential circuit blocks andmechanical parts of a camera provided with the device according to thefirst embodiment shown in FIG. 16 and described above with reference toFIGS. 1 to 15(a), 15(b).

The camera shown in FIG. 17 includes a plunger driving circuit 21 forturning on or off the plunger 16, a pulse signal detecting circuit 22for detecting the output pulse of the photocoupler 17, and a motordriving circuit 23 for turning on or off the motor 1 shown in severalfigures such as FIG. 1 and for providing control relative to rotation inthe “Rv” direction and rotation in the “Fw” direction. The circuits 21,22 and 23 are controlled by a control circuit 24. The shown camera alsoincludes the output gears 9 a to 9 d described previously, and the powerof a desired one of the output gears 9 a to 9 d is transmitted to thecorresponding one of the mechanisms (a lens-barrel driving system and afilm-transportation driving system) 25 a to 25 d through the associatedgear train (not shown but represented by a thick line), as describedpreviously with reference to FIG. 16. The resultant signal 26 a, 26 b,26 c or 26 d is fed back to the control circuit 24. The shown cameraalso includes a revolution-of-planetary-gear lock mechanism 27 made upof elements such as the arm 15, the rotation-stopping arm 12, the crownstopper 10 and the holding stopper 11.

The present device can be effectively utilized to achieve a number ofadvantages. Such advantages will be described below before a descriptionof the operation of the control circuit 24.

Advantage 1

If the helicoid gear 310 for making the lens barrel 314 retract iserroneously rotated with the lens barrel 314 retracted, that is, whenthe camera is placed in a non-photographic state with its main switchoff, the lens barrel 314 may move outward by accident. For this reason,when the main switch is off, the planetary gear 7 is held in mesh withthe output gear 9 a within the region {circle around (7)}. In thisarrangement, since the gear train 310 a which constitutes a system formoving the lens barrel 314 forward does not idle if the motor 1 is notactivated, it is possible to prevent the lens barrel 314 from movingoutward from a retracted position. However, as described previously inconnection with the “exit operation”, if it is impossible to determinein which direction (“Fw” or “Rv”) the end portion 12 c of therotation-stopping arm 12 is urged in engagement with the end face of thecutout of the crown stopper 10, the “exit operation” may fail when the“initial positioning” is to be performed, as by turning on the mainswitch. For this reason even after the completion of a retractingoperation, to prevent backlash from occurring among gears or otherassociated parts, they must be urged in their positions in thedirections in which they were respectively made to rotate during theretracting operation, and the lens barrel 314 must be fully urged in theretracting direction in its retracted position.

Manual rewinding of the film F may be performed with the main switchoff, and during the manual rewinding, the planetary gear 7 is meshedwith the output gear 9 d. If the planetary gear 7 is to be returned toits standby position in the region {circle around (7)} after thecompletion of the manual rewinding, the planetary gear 7 must be stoppedin the region {circle around (7)} in such a way that, in the case of the“entrance operation”, it can enter the region {circle around (7)} in amanner similar to that performed for a retracting operation.

As is apparent from the above description, since the motor 1 is stoppedwith the planetary gear 7 in mesh with an arbitrary one of the outputgears 9 a to 9 d, a gear train extending from the gear in mesh isprevented from idling and the mechanism of an element to which power isto be transmitted can be locked, whereby occurrence of an unwantedoperation can be prevented.

The above-described process is similarly performed during normalphotography (the main switch off), and the planetary gear 7 remains inmesh with the gear 9 c which is coupled to the zoom driving gear 312. Ina zooming operation, the motor 1 is driven to rotate in the “Fw” or “RV”direction with the planetary gear 7 in mesh with the gear 9 c. When filmwinding after a shutter release operation is to be performed, theplanetary gear 7 is made to mesh with the output gear 9 d coupled to thefilm-transportation driving system for the purpose of performing thefilm winding. After the completion of the film winding, the planetarygear 7 is again made to mesh with the output gear 9 c. The reasons whythe above-described operation is needed are that what an operator caneasily touch among the mechanism parts of the camera when the mainswitch is on is the lens barrel 314 or the lens tube 316 as viewed inFIG. 16, and that the lens barrel 316 easily moves at a touch. However,in the state wherein the planetary gear 7 is in mesh with the outputgear 9 c, the lens barrel 314 does not move since it is fixed by thebayonet ring 311.

The above-described two kinds of gear locking are performed inaccordance with the flow “OPERATION OF MOVING LENS BARREL BACKWARD” ofFIG. 24 and the flow “ZERO POSITION” of FIG. 30, both of which will bedescribed later.

As described above, after the completion of power transmission, theplanetary gear 7 remains in mesh with any one of the output gears 9 a to9 d or is combined with an arbitrary output gear, whereby a mechanismextending from the output gear in mesh is prevented from idling.Accordingly, the present device may be regarded not only as a device formerely effecting power transmission but also as a lock device forlocking the operation of each mechanism.

Advantage 2

During normal photography, after film winding has been performed foreach shutter release operation, the planetary gear 7 is placed in meshwith the output gear 9 c so that the lens tube 316 is not moved exceptfor a zooming operation. However, during a continuous photography mode,since no zooming operation is performed, the planetary gear 7 remains inmesh with the output gear 9 d and the start and stop of the motor 1 arerepeated.

As described above, since a normal control mode (for the normalphotography) and a continuous power transmission mode (for thecontinuous photography mode) are provided, during the continuous powertransmission mode, the start and stop of the motor 1 need only berepeated and the plunger 16 or the photocoupler 17 need not be made toperform an unessential operation. Accordingly, only a power transmissionoperation is needed and a power dividing operation can be omitted.

Advantage 3

In accordance with the present invention, it is possible to selectarbitrarily an element to which power is to be transmitted, unlike aconventional power transmission and distributing mechanism in which anelement to which power is to be transmitted is selected sequentially intime by using a differential mechanism or the like. As a result, thereis also a possibility that an error in the selection of an element towhich power is to be transmitted (dividing error) will occur. In thecase of a dividing error, as described above, the state of the dividingerror can be identified from the drive signals 26 a to 26 d which arefed back to the control circuit 24 shown in FIG. 17.

As is apparent from the above description, by providing a routine whichis designed to perform, if a dividing error occurs, the “initialpositioning” operation and again select an appropriate element to whichpower dividing is to be directed, it is possible to achieve theadvantage that if the power dividing mechanism malfunctions, optimumrestoration processing can be performed.

If the planetary gear 7 does not correctly operate and meshes with awrong one of the output gears 9 a, 9 b, 9 c or 9 d although the “initialpositioning” operation is performed several times, it is preferable thatan “inhibit mode” for making the camera inoperative be provided.

The operation of the control circuit 24 shown in FIG. 17 will bedescribed below with reference to FIGS. 18 to 31.

First, the outline of a series of operations of the camera will bedescribed below with reference to the main flowchart of FIG. 18.

Step #70: If battery replacement is performed, all information is reset,and information indicating in which of the regions X to {circle around(8)} the planetary gear 7 is positioned is cancelled. Accordingly, the“initial positioning” operation is performed (which will be describedlater in detail with reference to FIG. 19).

Step #71: It is determined whether the main switch is on. If it is on,the process proceeds to Step #72, while if it is off, the processproceeds to Step #82.

Step #72: It is determined whether the lens barrel 314 is placed in itsforward position. If the lens barrel 314 is placed in the forwardposition and photography can be performed, the process proceeds to Step#73. If the lens barrel 314 is placed in its retracted position, theprocess proceeds to Step #79 “OPERATION FOR MOVING LENS BARREL FORWARD”.

Step #73: It is determined whether a shutter release switch is on oroff. If it is on, the process proceeds to Step #84 to perform theoperations, such as exposure and winding operations, shown in Step #84and the subsequent steps. If it is off, the process proceeds to Step#74.

Steps #74 and #75: It is determined whether a telephoto switch or awide-angle switch is on or off. If either is on, the process proceeds toStep #80 or #81 to perform a telephoto zooming operation or a wind-anglezooming operation. If both are off, the process proceeds to Step #76.

Step #76: It is determined whether a manual rewinding switch is on oroff. If it is off, the process proceeds to Step #77, while if it is on,the process proceeds to Step #91 to perform the operations shown in Step#91 and the subsequent steps.

Step #77: It is determined whether a back lid has been opened or closed.If it is determined that a closing operation has been performed, theprocess normally proceeds to Step #78 “AUTOMATIC LOADING” to perform afilm loading operation. If not, the process returns to Step #71.

Step #78: An automatic loading operation is performed (as will bedescribed later in detail with reference to FIG. 25).

Step #79: An operation for moving the lens barrel 314 forward isperformed (as will be described later in detail with reference to FIG.23).

Step #80: The telephoto zooming operation is performed (as will bedescribed later in detail with reference to FIG. 26).

Step #81: The wide-angle zooming operation is performed (as will bedescribed later in detail with reference to FIG. 27).

Step #82: Since it has been determined in Step #71 that the main switchis off, it is determined whether the lens barrel 314 is placed in itsretracted position. If the lens barrel 314 is not retracted, the processproceeds to Step #83 “OPERATION FOR MOVING LENS BARREL BACKWARD”. If thelens barrel 314 has been retracted, it is determined that the mainswitch is off under normal conditions, and the process proceeds to Step#76 described previously.

Step #83: The operation for moving the lens barrel 314 backward isperformed (as will be described later in detail with reference to FIG.24).

Steps #84 and #85: Normal exposure and winding operations of the film Fare performed. The details of the winding operation will be describedlater with reference to FIG. 28.

Step #86: After the film F has been wound up to the trailing end, it isdetermined whether the film F is in a stretched state. If the film F isin the stretched state, the process proceeds to step #91, while if ithas been wound up normally, the process proceeds to Step #87.

Step #87: It is determined whether a continuous shooting mode switch ison or off. If it is off, this indicates that a single-frame photographymode has been selected, and the process proceeds to Step #89. If acontinuous shooting mode has been selected, the process proceeds to Step#88.

Step #88: It is determined whether the shutter release switch remainson. If it is on, the process returns to Step #71 to carry on continuousshooting, and a photographic operation similar to the above-describedoperation is repeated. If the shutter release switch is turned off, thecontinuous shooting is stopped, and the process proceeds to Step #89, asin the case of the single-frame photography mode.

Step #89: After a photographic operation such as the exposure operation,the zooming operation or the manual rewinding operation has beencompleted with the camera on, a zero-positioning operation is performedin which the lens tube 316 is locked with the planetary gear 7 meshedwith the gear train 312 a of the lens-barrel driving system.

Step #90: It is determined whether the shutter release switch is off,and the process stays in this step until it is turned on.

The “initial positioning” operation will be described below withreference to FIG. 19.

Step #1: The process jumps to this subroutine from Step #70 or #91 ofFIG. 18 or from Step #141 or #147 of FIG. 25, and the “initialpositioning” operation shown in Step #2 and the subsequent steps isstarted.

Step #2: The plunger 16 is turned on (activated) via the plunger drivingcircuit 21. The rotation-stopping arm 12 has not yet disengaged from thecrown stopper 10 and is engaged with the aforementioned “edge portion”of the holding stopper 11 (the state shown in FIGS. 10(a) and 10(b)).

Step #3: To remove the backlash of the gears and to disengage therotation-stopping arm 12 from the holding stopper 11, the motor 1 isdriven to rotate in a direction reverse to the immediately precedingdirection of rotation before the “initial positioning” operation (aswill be described later in detail with reference to FIG. 20) is started.

Steps #4 to #7: The planetary gear 7 is made to revolve up to the region{circle around (8)}, and the end portion 12 c of the rotation-stoppingarm 12 is brought into abutment with the erected portion 10 c of thecrown stopper 10 (the state shown in FIGS. 5(a), 5(b) and 5(c)).

In Steps #4 to #7, the operation of detecting the position of theplanetary gear 7 during revolution by means of the pulse disc 14 is notcarried out. Instead, the motor 1 is driven to rotate unconditionallyfor a sufficient time (in this example, 500 msec) for the planetary gear7 to revolve in one direction from the region X to the region {circlearound (8)} or vice versa, thereby merely bringing the end portion 12 cof the rotation-stopping arm 12 into abutment with the erected portion10 c of the crown stopper 10. Thus, the planetary gear 7 is capable ofmoving directly to the region {circle around (8)}, or of first movingtoward the region X and then reversing to the region {circle around(8)}, depending on the direction in which the end portion 12 c exitsfrom the cutout of the crown stopper 10.

Step #8: Since the planetary gear 7 is positioned in the region {circlearound (8)}, “8” is substituted into a register n. In this step,however, the positioning of the planetary gear 7 in the region {circlearound (8)} is not based on pulse counting, and it is merely assumedthat the planetary gear 7 ought to be positioned in the region {circlearound (8)} as a result of the unconditional rotation of the motor 1. Ifthe planetary gear 7 is actually not positioned in the region {circlearound (8)}, this indicates the occurrence of a rotation failure of therotating arm 5 or other elements and hence the occurrence of anoperation failure of the power dividing device.

Step #9: The motor 1 is driven to rotate in the “Rv” direction, therebycausing the planetary gear 7 to revolve from the region {circle around(8)} to the region X (the initial position 10 d).

Step #10: A pulse transition is detected in this step. Specifically,while the planetary gear 7 is revolving from the region {circle around(8)} to the region X, each time a pulse transition from the “bright”level to the “dark” level or vice versa is detected, the value of theregister n is decremented by one. If n=0 is reached and the planetarygear 7 enters the region X or no pulse transition occurs during apredetermined time period, the process proceeds to Step #11. The detailsof the operation in Step #11 will be described later with reference toFIG. 21.

Step #11: It is determined that the end portion 12 c of therotation-stopping arm 12 has entered the area between the end face 10 eand the erected portion 10 c of the crown stopper 10, and the drive ofthe sun gear 6 and the motor 1 is stopped.

Step #12: It is determined whether the “initial positioning” operationhas been correctly performed. If the planetary gear 7 correctly revolvesfrom the region {circle around (8)} to the region X, pulse transitionsoccur eight times. In this step, therefore, the value of the register nshould be “0”. However, if the revolution of the planetary gear 7 ishindered for a certain reason, “n≧1” (n≠0) is obtained. If “n=0”, theprocess proceeds to Step #13, while if “n≧1”, the process proceeds toStep #14.

Step #13: Since the “initial positioning” operation has been correctlyperformed, the planetary gear 7 is positioned in the region X, morespecifically, in the region of the initial position 10 d. Therefore, theregion (position), P0, where the planetary gear 7 is positioned isassigned “0”.

Step #14: Since the “initial positioning” operation has not beencorrectly performed, it is determined that the planetary gear 7 hasfailed to revolve correctly, and an inhibit mode is selected.

Step #15: This subroutine is brought to an end, and the process returnsto the main routine.

The operation named “ENERGIZE MOTOR IN REVERSE DIRECTION” will bedescribed below with reference to FIG. 20.

Step #20: In Step #3 of FIG. 19 or Step #39 of FIG. 22, the processjumps to this subroutine, and starts the operation named “ENERGIZE MOTORIN REVERSE DIRECTION”, shown in Step #21 and the subsequent steps.

Steps #21, #22 and #24: The present direction of rotation of the motor1, or, if the motor 1 is inoperative, the preceding direction ofrotation of the same, is identified. The motor 1 is driven in adirection reverse to the identified direction of rotation.

Steps #23 and #25: The new direction of rotation is memorized as thepresent direction of rotation.

Step #26 and #27: This subroutine is brought to an end, and the processreturns to the main routine.

The operation named “COUNT PULSE” will be described below with referenceto FIG. 21.

Step #61: In Step #10 of FIG. 19 or in any one of Steps #41, #46, #50and #54 of FIG. 22, the process jumps to this subroutine, and starts theoperation named “COUNT PULSE”, shown in Step #62 and the subsequentsteps. This subroutine has a flow for counting the number of pulsetransitions, and each time a pulse transition of either “bright→dark” or“dark→bright” occurs, a counting operation is performed once. As aninitial setting, n is determined as the number of pulse transitionsoccurring from the start of a particular revolution of the planetarygear 7 in the present state until the end of the revolution.

Step #62: A timer is started each time a pulse transition occurs inorder to determine whether no pulse transition occurs during apredetermined time period or more while the revolution of the planetarygear 7 is stopped, for example, while the planetary gear 7 is positionedin the region X or {circle around (8)} and the revolution in the “Fw” or“Rv” direction is stopped in the state shown in FIGS. 5(a), 5(b) and5(c) or FIGS. 7(a), 7(b) and 7(c), or in a case where the revolution isstopped due to any trouble.

Step #63: A pulse transition from the “dark” level to the “bright” levelor vice versa is detected. If no such transition is detected, theprocess proceeds to Step #64, while if it is detected, the processproceeds to Step #65.

Step #64: If there is no pulse transition, it is determined whether thepredetermined time period has elapsed. If the predetermined time periodhas not elapsed, the process returns to Step #62, where the processwaits for a pulse transition. If it has elapsed, the process proceeds toStep #67.

Steps #65 and #66: Since the pulse transition has occurred, the value ofthe register n which indicates the number of pulse transitions isdecremented by one. As a result, if “n=0” is reached, it is determinedthat the required amount of revolution of the planetary gear 7 has beencompleted, and the process proceeds to Step #67. This subroutine isbrought to an end, and the process returns to the main routine.

The operation named “POWER DIVIDING” will be described below withreference to FIG. 22, but symbols which will be used in the followingdescription are explained with reference to FIG. 31.

As shown in FIG. 31, P0 indicates a position where the planetary gear 7is presently located, P1 a position to which the planetary gear 7 is tomove, M0 the direction of the past rotation of the motor 1, M1 thedirection of motor rotation of a load at the position to which theplanetary gear 7 is to move, and M2 the direction in which the rotatingarm 5 is moved. The relationships between driving operations, dividingpositions and the directions of rotation of the motor 1 are as shown.

Step #30: In Step #102 or #108 of FIG. 23 or in Step #125 or #128 ofFIG. 24, the process jumps to this subroutine, and starts the operationnamed “POWER DIVIDING”, shown in Step #31 and the subsequent steps. Atthe time of this operation, the position P1 of the desired one of theoutput gears 9 a to 9 d to which power is to be transmitted and thedirection M1 of motor rotation of the desired output gear, are inputted.The output gears 9 a to 9 d correspond to the positions {circle around(7)}, {circle around (5)}, {circle around (3)} and {circle around (1)},respectively.

Steps #31 and #31′: It is determined whether the position (P0) of theoutput gear with which the planetary gear 7 is presently meshed is thesame as the position (P1) of the output gear at the desired position. Ifboth are the same (P0=P1), the motor 1 is driven to rotate in the M1direction. Otherwise, the process proceeds to Step #32.

Step #32: It is determined in which direction the planetary gear 7should be made to revolve, that is, whether P1>P0. If P1>P0, the processproceeds to Step #35; otherwise, the process proceeds to Step #33.

Steps #33 to #36: The direction M2 of rotation of the rotating arm 5(i.e., the direction of revolution of the planetary gear 7) is set to“Rv” or “Fw”. The number of pulse transitions which will occur until theplanetary gear 7 reaches the desired one of the output gears 9 a to 9 dis calculated (P1−P0), and the obtained value is stored in the registerN.

Then, the process enters into the “exit operation”.

Step #37: The plunger 16 is turned on. If the plunger 16 remains on, therotation-stopping arm 12 is engaged with the aforementioned “edgeportion” of the holding stopper 11.

Step #38: Whether the direction M2 of rotation of the rotating arm 5 isthe same as the direction in which the rotation-stopping arm 12 comesinto abutment with the crown stopper 10 is determined by determiningwhether M2=M0. If both are the same, the process proceeds to Step #39since it is necessary to reverse the motor 1 to remove the backlash asdescribed previously.

Steps #39 to #42: The motor 1 is driven to rotate in a direction reverseto the immediately preceding direction of rotation before the processenters the “exit operation”, and a pulse transition (“bright”→“dark”)indicating that the rotation-stopping arm 12 has disengaged from theholding stopper 11 is detected (as shown at 201 in FIGS. 12(a) and13(a)). If no pulse transition is detected, the process proceeds to Step#59 “INHIBIT MODE”.

Step #43: Since the rotation-stopping arm 12 has disengaged in thedirection reverse to the M2 direction, the pulse transition(“bright”→“dark”) is detected once. Therefore, the number of pulsetransitions up to the desired one of the output gears 9 a to 9 d isincremented by one (N+1).

Step #44: Revolution of the planetary gear 7 toward the desired one ofthe output gears 9 a to 9 d is started.

In this step, the “exit operation” comes to an end.

Steps #45 to #47: The planetary gear 7 is made to revolve up to aposition in which a “dark” pulse appears which immediately precedes a“bright” pulse indicative of the desired one of the output gears 9 a to9 d. If such revolution fails and no pulse transition occurs during apredetermined time period, the process proceeds to Step #59.

Then, the process enters the “entrance operation”.

Step #48: After the completion of this flow, if the motor 1 is driven torotate further in the same direction, power is transmitted in thatdirection of motor rotation. By determining whether M1=M2, it isdetermined whether the direction M2 in which the rotating arm 5 hasrotated (the direction of revolution of the planetary gear 7) is thesame as the direction of rotation of the motor 1 during the powertransmission. If both are the same, the process proceeds to Step #56;otherwise, the process proceeds to Step #49.

Steps #49 to #51: These steps constitute the initial part of the flow inwhich the planetary gear 7 starts power transmission after it has passedthe desired one of the output gears 9 a to 9 d and turned the directionof revolution toward the desired output gear. It is checked whether a“dark” signal (shown at 202 in FIGS. 14(a) and 15(a)) indicating thatthe planetary gear 7 has come out of mesh with the desired one of theoutput gears 9 a to 9 d is detected from a “bright” signal indicatingthat the planetary gear 7 is in mesh with the desired output gear. Ifsuch a “dark” signal is not detected, the process proceeds to Step #59,while if it is detected, the process proceeds to Step #52.

Steps #52 to #55: The planetary gear 7 starts turning the direction ofrevolution toward the desired output gear. The motor 1 is driven torotate in the direction of power transmission. It is checked whether a“dark→bright” signal (shown at 204 in FIGS. 14(a) and 15(a), as well asshown at 204′ in FIGS. 14(b) and 15(b)) is detected which indicates thatthe planetary gear 7 has meshed with the desired one of the output gears9 a to 9 d. If such a “dark” signal is not detected, the processproceeds to Step #59, while if it is detected, the process proceeds toStep #56.

Step #56: The plunger 16 is turned off. Thus, the end portion 12 c ofthe rotation-stopping arm 12 slides on the holding stopper 11 and entersthe cutout of the crown stopper 10, so that the revolution of theplanetary gear 7 is stopped and only the rotation of the planetary gear7 on its axis is allowed, thereby causing power transmission to start.

In this step, the “entrance operation” is brought to an end.

Step #57: The position P0 where the planetary gear 7 is presentlylocated and the direction M0 of rotation of the motor 1 are memorized.

Step #58: This subroutine is brought to an end, and the process returnsto the main routine.

Step #59: The plunger 16 and the motor 1 are turned off.

Step #60: The inhibit mode for making the camera inoperative is set.

The operation named “OPERATION FOR MOVING LENS BARREL FORWARD” will bedescribed below with reference to FIG. 23.

Step #100: In Step #79 of FIG. 18, the process jumps to this subroutine,and starts the operation named “OPERATION FOR MOVING LENS BARRELFORWARD” shown in Step #101 and the subsequent steps.

Steps #101 and #102: The helicoid gear 310 is made to rotate, causingthe planetary gear 7 to revolve in the direction in which the lensbarrel 314 moves forward (P1=7, M1=Fw), thereby meshing the planetarygear 7 with the output gear 9 a and transmitting power through the geartrain 310 a.

Step #103: The motor 1 is driven to rotate until the forward movement ofthe lens barrel 314 has been completed. If the completion is detected,the process proceeds to Step #104.

Steps #104 to #106: The driving operation is specified as “P1=5, M1=Rv”so that the bayonet ring 311 is made to rotate in the lock direction,and the motor 1 is driven to rotate until the bayonet ring 311 fixes thelens barrel 314 by means of the power transmitted through the gear train311 a from the output gear 9 b.

Steps #107 to #110: The zoom driving gear 312 is made to rotate, therebymoving the lens tube 316 forward up to its wide-angle end by means ofthe cam ring 315.

Step #111: This subroutine is brought to an end, and the process returnsto the main routine.

The operation named “OPERATION FOR MOVING LENS BARREL BACKWARD” will bedescribed below with reference to FIG. 24.

Step #120: In Step #83 of FIG. 18, the process jumps to this subroutine,and starts the operation named “OPERATION FOR MOVING LENS BARRELBACKWARD” shown in Step #121 and the subsequent steps.

Steps #121 to #123: “P1=3, M1=Rv” is specified to cause the planetarygear 7 to revolve and mesh with the output gear 9 c, thereby causing thezoom driving gear 312 to rotate so that the lens tube 316 is moved intothe lens barrel 314 by means of the cam ring 315.

Steps #124 to #126: “P1=5, M1=Fw” is specified to cause the planetarygear 7 to revolve and mesh with the output gear 9 b, thereby causing thebayonet ring 311 to rotate so that the lens barrel 314 is unlocked.

Steps #127 to #129: “P1=7, M1=Rv” is specified to cause the planetarygear 7 to revolve and mesh with the output gear 9 a, thereby causing thehelicoid ring 310 to rotate so that the lens barrel 314 is retracted.

Step #130: The motor 1 is turned of f with the backlash of the geartrain 310 a remaining in a direction corresponding to the backwardmovement of the lens barrel 314. Thus, the lens barrel 314 is preventedfrom moving outward by accident.

Step #131: This subroutine is brought to an end, and the process returnsto the main routine.

The operation named “AUTOMATIC LOADING” will be described below withreference to FIG. 25.

Step #140: In Step #78 of FIG. 18, the process jumps to this subroutine,and starts the operation named “AUTOMATIC LOADING”, shown in Step #141and the subsequent steps.

Step #141: The above-described “initial positioning” operation isperformed to bring the planetary gear 7 to the initial position.

Steps #142 and #143: “P1=1, M1=Rv” is specified to cause the planetarygear 7 to revolve and mesh with the output gear 9 d, causing theplanetary gear 7 to rotate so that the output gear 9 d is made to rotatein the direction of film winding, thereby performing power transmission.Thus, the planetary gear 304 for film transportation which constitutes ageneral gear mechanism rotates with a planetary arm 309 for filmtransportation and meshes with a winding gear (not shown), therebycausing a spool 305 to rotate. Thus, winding of the film F from a filmcartridge 313 is started.

Steps #144 to #146: Normal automatic loading is performed.

Steps #147 and #149: These steps constitute a flow which is executed ifthe automatic loading fails. The “initial positioning” operation isperformed, and the back lid is usually opened since it is necessary toagain put the film F in position. When it is opened, the processproceeds to the next step.

Step #148: This step constitutes a flow through which the processproceeds when the automatic loading is to be completed, and theoperation named “ZERO POSITION” is performed (as will be described belowin detail with reference to FIG. 30).

Step #150: This subroutine is brought to an end, and the process returnsto the main routine.

The operation named “TELEPHOTO ZOOMING” will be described below withreference to FIG. 26.

Step #180: In step #80 of FIG. 18, the process jumps to this subroutine,and starts the operation named “TELEPHOTO ZOOMING”, shown in Step #181and the subsequent steps.

Steps #181 and #182: “P1=3, M1=Fw” is specified to cause the planetarygear 7 to revolve and mesh with the output gear 9 c, and the planetarygear 7 in mesh is made to rotate in the telephoto direction whileperforming power transmission through the output g ear 9 c.

Steps #183 to #185: A normal telephoto zooming operation is performedthrough the gear train 312 a and the zoom driving gear 312.

Step #186: This subroutine is brought to an end, and the process returnsto the main routine.

The operation named “WIDE-ANGLE ZOOMING” will be described below withreference to FIG. 27.

Step #190: In Step #81 of FIG. 18, the process jumps to this subroutine,and starts the operation named “WIDE-ANGLE ZOOMING”, shown in Step #191and the subsequent steps.

Steps #191 and #192: “P1=3, M1=Rv” is specified to cause the planetarygear 7 to revolve and mesh with the output gear 9 c, and the planetarygear 7 is made to rotate in the wide-angle direction by performing powertransmission through the output gear 9 c.

Steps #193 to #195: A normal wide-angle zooming operation is performedthrough the gear train 312 a and the zoom driving gear 312, as in theabove-described “TELEPHOTO ZOOMING”.

Step #196: This subroutine is brought to an end, and the process returnsto the main routine.

The operation named “WINDING” will be described below with reference toFIG. 28.

Step #160: In Step #85 of FIG. 18, the process jumps to this subroutine,and starts the operation of winding the film F.

Steps #161 and #162: “P1=1, M1=Rv” is specified to cause the planetarygear 7 to revolve and mesh with the output gear 9 d, and the spool 305is made to rotate through the output gear 9 d and the gear 304 as wellas a gear 308 both of which are provided for film transportation.

Steps #163 to #165: A normal winding operation for the film F isperformed.

Step #166: This subroutine is brought to an end, and the process returnsto the main routine.

The operation named “REWINDING” will be described below with referenceto FIG. 29.

Step #170: In Step #92 of FIG. 18, the process jumps to this subroutine,and starts the operation of rewinding the film F.

Steps #171 and #172: Since the position where the planetary gear 7 ismade to revolve is “P1=1”, similar to the position specified for theabove-described winding operation, the planetary gear 7 meshes with theoutput gear 9 d. However, since the direction of rotation of theplanetary gear 7 is “M1=Fw”, the output gear 9 d also rotates in the“Fw” direction. Accordingly, the planetary gear 304 for filmtransportation causes the winding gear 308 for film transportation torotate, thus causing a fork gear (not shown) to rotate.

Steps #173 to #175: A normal rewinding operation for the film F isperformed.

Step #176: The operation named “ZERO POSITION” which will be describedlater is performed.

Step #177: This subroutine is brought to an end, and the process returnsto the main routine.

The operation named “ZERO POSITION” will be described below withreference to FIG. 30.

Step #200: In Step #89 of FIG. 18, in Step #148 of FIG. 25 or in Step#176 of FIG. 29, the process jumps to this subroutine, and starts theoperation named “ZERO POSITION”, shown in Step #201 and the subsequentsteps. As described previously, the “zero position” operation is theoperation of preventing the lens tube 316 or the lens barrel 314 frommoving by accident, for example, by keeping the planetary gear 7 meshedwith the output gear 9 c for zooming when the main switch is on, or withthe output gear 9 a when the main switch is off.

Step #201: It is determined whether a lens-barrel backward switch is onor off. If it is on, it is determined that the main switch is off, andthe process proceeds to Step #204. If it is off, it is determined thatthe main switch is on, and the process proceeds to Step #202.

Steps #202 and #203: “P1=3, M1=Fw” is specified to cause the planetarygear 7 to revolve and mesh with the output gear 9 c which is coupled tothe zooming mechanism. Thus, in the next photographic cycle, a zoomingoperation can be immediately initiated. Since the above-describedoperation serves also as a lock function for the lens tube 316, even ifthe lens tube 316 is pushed by accident, no serious trouble takes place.Only when the process jumps to this subroutine in Step #89 of FIG. 18,does the flow proceed from Step #201 to Steps #202 and #203.

Steps #204 to #206: A small retracting operation is performed with theplanetary gear 7 remaining in mesh with the output gear 9 a. The lensbarrel 314 actually does not move since it is retracted, but it ispossible to reliably lock the lens barrel 314 by holding the gear train310 a and the helicoid gear 310 under a certain amount of tension (withbacklash remaining). Only when the process jumps to this subroutine inStep #148 of FIG. 25 or Step #176 of FIG. 29, does the flow proceed fromStep #201 to Steps #204 to #206.

Step #207: The motor 1 is turned off. Accordingly, as long as the motor1 is not activated as described above, the lens tube 316 or the lensbarrel 314 does not move.

Step #208: This subroutine is brought to an end, and the process returnsto the main routine.

According to the above-described first embodiment, during the “entranceoperation”, the direction of power transmission of the desired one ofthe output gears 9 a to 9 d to which power dividing is to be directed ismade the same as the direction of revolution of the planetary gear 7, sothat there is no need to change the direction of rotation of the motor 1(the sun gear 6). Accordingly, a mechanism to which the power is to betransmitted is prevented from being reversed in an unexpected direction.In addition, it is possible to smoothly perform subsequent operations.

As described above, according to the first embodiment, power-dividingcontrolling means for causing a planetary gear to mesh with a specifiedoutput gear and causing the output gear to selectively transmit thedriving power of the sun gear is provided with rotational directioncontrolling means for determining whether the direction in which theplanetary gear is made to revolve for selection of the output gear isthe same as the direction in which the output gear is made to rotateafter the planetary gear is held by holding means, and, if bothdirections differ, making the direction of rotation of the planetarygear coincide with the direction of rotation of the output gear and thenmeshing them with each other, whereby the direction in which theplanetary gear is made to revolve for selection of the output gear ismade the same as the direction in which the output gear is made torotate after the planetary gear is held by the holding means. In thisarrangement, the direction of rotation of the sun gear immediatelybefore it meshes with the output gear is the same as the direction ofrotation of the output gear. Accordingly, the output gear and amechanism to which power is to be transmitted are prevented fromoperating in reverse directions when the sun gear and the output gearmesh with each other. In addition, it is possible to smoothly performthe subsequent power transmission operations.

According to the above-described first embodiment, since the holdingstopper 11 serving as lock means is disposed above the crown stopper 10,it is possible to reliably perform the switching operation of theplanetary gear 7 to change an element to which power is to betransmitted. More specifically, since the planetary gear 7 does notdisengage from the holding stopper 11 until backlash is removed, anunwanted force generated from the backlash does not act on the powertransmission mechanism. Further, there is no need to strictly controlthe characteristics of the torsion springs 13 b and 15 c as well as theplunger 16, the variations of the frictional force between the crownstopper 10 and the rotation-stopping arm 12 due to the tolerance of theshape of an actual part which is used as the crown stopper 10 or therotation-stopping arm 12.

Further, as is apparent from the above description, according to thefirst embodiment, power-dividing controlling means for causing aplanetary gear to mesh with a specified output gear and causing theoutput gear to selectively transmit the driving power of the sun gear isprovided with mesh releasing means for releasing the mesh between thesun gear and an output gear which is in mesh therewith, after removingbacklash by causing the sun gear to rotate in a reverse direction, if aninstruction to change an element to which power is to be transmitted.The power-dividing controlling means is also provided with lock meansfor holding the mesh between the sun gear and the output gear until thebacklash of the sun gear is removed, when the mesh between the sun gearand the planetary gear is to be released by the mesh releasing means. Inthe above-described arrangement, the mesh between the planetary gear andthe output gear is not released until the backlash is removed, that is,until an unwanted revolving force which is applied to the planetary gearowing to the backlash is eliminated. Accordingly, it is possible toprovide reliable control over the revolution of the planetary gear whenit is necessary to change an element to which power is to betransmitted.

According to the first embodiment, after the completion of a filmwinding operation, it is determined whether the presently selectedphotography mode is the normal photography mode or thecontinuous-shooting photography mode. If the normal photography mode isactive, the planetary gear 7 is switched from the output gear 9 d withwhich it is presently meshed to the output gear 9 c (the lens tube 316)(as shown in Steps #87→#89 of FIG. 18 (more specifically, in Steps#200→#201→#202→#203→#207 of FIG. 30)). This is because the probabilitythat power transmission will be performed initially in the nextphotographic cycle is high (because it is necessary to ensure theresponse speed at which the next photographic cycle is started), andbecause it is necessary to prevent the lens tube 316 from moving if itis accidentally pushed (a lock function works by holding the planetarygear 7 and the output gear 9 c in mesh with each other).

If the continuous-shooting photography mode is active, the first elementto which power is to be transmitted in the next photographic cycle isstill a film transporting mechanism coupled to the output gear 9 d.Therefore, the planetary gear 7 is not made to revolve and remains inmesh with the output gear 9 c. Accordingly, the unwanted operations ofthe plunger 16 and the pulse disc 14 can be eliminated and it ispossible to provide effective control over power dividing merely byperforming control of the repetition of start and stop of the motor 1.

As described above, according to the first embodiment, there is provideda power-dividing-position instructing means for instructing, if thenormal photography is identified by photography-mode identifying means,the power-dividing controlling means to switch the planetary gear froman output gear coupled to a film transporting mechanism to an outputgear coupled to a lens-barrel driving mechanism after a film windingoperation has been performed after the completion of photography, or forinstructing, if the continuous-shooting photography is identified by thephotography-mode identifying means, the power-dividing controlling meansto maintain the planetary gear in mesh with the output gear coupled tothe film transporting mechanism. In the above-described arrangement, ifone-frame photography, i.e., the normal photography, is performed, theplanetary gear is switched to the output gear coupled to a lens-barreldriving mechanism to which power is to be next transmitted, while ifcontinuous photography is performed, the planetary gear is held in meshwith the output gear coupled to the film transporting mechanism sincepower transmission for the film transporting mechanism is againperformed in the next exposure operation. Accordingly, it is possible toachieve effective power transmission, particularly when thecontinuous-shooting mode is selected.

According to the first embodiment, the planetary gear 7 is held in meshwith the output gear 9 c after the completion of film winding, or duringphotography with the main switch on, the planetary gear 7 is held inmesh with the output gear 9 c after the completion of automatic loadingor film rewinding (refer to FIG. 30). Accordingly, even if the lens tube316 or the lens barrel 314 is pushed by accident, it does not idle. Whenthe main switch is off, after the lens barrel 314 has retracted by meansof the retracting operation of the helicoid gear 310, the planetary gear7 is held in mesh with the output gear 9 a coupled to the helicoid gear310. In the above-described arrangement, the lens barrel 314 isprevented from moving outward due to accidental factors such as thevibration of the camera.

As described above, according to the first embodiment, after thecompletion of a power transmission operation, the planetary gear isselectively made to mesh with an output gear coupled to a mechanismwhich may be accidentally exposed to an external force, whereby themechanism is prevented from moving unexpectedly.

According to the first embodiment, the portion (12 d) which is definedon the rotation-stopping arm 12 on a line extending from the rotatingshaft (output shaft) 3 is pressed by the projection 15 e of the arm 15,so that the end portion 12 c is made to enter an arbitrary cutout of thecrown stopper 10. Accordingly, it is possible to reliably lock theplanetary gear 7 and the selected one of the output gears 9 a to 9 dirrespective of the position of the rotation-stopping arm 12. Inaddition, since the construction is extremely simple, the size of theapparatus does not increase.

As described above, according to the first embodiment, in a statewherein the planetary gear revolving around the sun gear has finishedrevolving up to the position of a specified output gear, the portionwhich is defined on a rotation-stopping member on a line extending fromthe rotating shaft of the sun gear is pressed in the direction of therotating shaft, to bring an engagement portion provided on therotation-stopping member into engagement with a stopper member, therebyholding the mesh of the planetary gear with the selected output gear.Thus, it is possible to reliably limit the revolution of the planetarygear by means of a simple arrangement.

According to the first embodiment, there is provided the erected portion10 c which inhibits the planetary gear 7 from meshing with any of theoutput gears 9 a to 9 d at an abutment position beyond which theplanetary gear 7 does not revolve further, and such an abutment positionis set as an initial position where the planetary gear 7 can rotate onits axis without revolution. Accordingly, when the planetary gear 7 isactivated at that position so as to revolve toward a desired one of theoutput gears 9 a to 9 d, the rotation of the planetary gear 7 is notaccidentally transmitted to the output gears 9 a to 9 d even if theplanetary gear 7 rotates at that position.

As described above, according to the first embodiment, when theplanetary gear is to be brought into mesh with a specified output gear,the planetary gear is first brought into abutment with a limiting memberwhich defines the revolution abutment position, that is, the initialposition. However, since the limiting member is provided at a positionwhere it is not meshed with any output gear, when the planetary gear ismoved in the initial position, the rotation of the planetary gear is notaccidentally transmitted to the output gear connected to the powertransmission mechanism.

According to the first embodiment, in the above-described device inwhich the position of the planetary gear 7 during revolution isidentified on the basis of the number of relative transitions of a pulsesignal or the like, during an “initial positioning” operation, when theposition of the planetary gear 7 during revolution is to be determined,the motor 1 is energized to rotate unconditionally in one directionduring a predetermined time period, thereby causing the planetary gear 7to revolve up to one abutment position in that direction. Then, themotor 1 is energized to rotate in the reverse direction, thereby causingthe planetary gear 7 to revolve in the reverse direction toward theother abutment position. During the above-described operation, it isdetected whether prescribed pulse signals are outputted. Accordingly, itis possible to perform a check of the operation of the devicesimultaneously with the “initial positioning” operation.

As described above, according to the first embodiment, power-dividingcontrolling means for bringing the planetary gear into mesh with aspecified output gear on the basis of an output from position detectingmeans after the completion of the “initial positioning” operation of theplanetary gear with respect to the limiting member, and causing thespecified output gear to selectively transmit the driving power of thesun gear, is provided with initial-positioning instructing means andoperation checking means. The initial-positioning instructing meanscauses the planetary gear to revolve up to a second limiting memberwhich defines a revolution abutment position in a second direction, andthen causes the planetary gear to revolve in the reverse direction up toa first limiting member which defines a revolution abutment position ina first direction. The operation checking means performs an operationcheck on the planetary gear on the basis of the output of the positiondetecting means during the revolution of the planetary gear from therevolution abutment position provided in the second direction up to therevolution abutment position provided in the first direction and definedas the initial position, that is to say, according to whether the numberof pulse transitions obtained through the position detecting meansduring the revolution from the revolution abutment position in thesecond direction up to the revolution abutment position in the firstdirection reaches a prescribed number of pulse transitions. In theabove-described arrangement, it is also possible to performsimultaneously a check on whether the revolution of the planetary gearis correctly performed during the “initial positioning” operation.

According to the first embodiment, in an operation step in which aseries of photographic control steps of the camera is not adverselyaffected even if the “initial positioning” operation is performed, suchas an automatic loading operation, a manual rewinding operation or afilm rewinding operation after film has been stretched, each time anelement to which power is to be transmitted is selected immediatelybefore any one of the above-described operations, the “initialpositioning” operation is carried out. Accordingly, it is possible toremarkably lower the probability that an error will occur such as theerroneous selection of an element to which power is to be transmitted.Since the “initial positioning” operation is actively performed only inthe aforesaid operation step in which the sequence of photographiccontrol steps is not adversely affected, it is possible to preventproblems such as the problems that a shutter opportunity is missed andthat a time lag for photography increases.

As described above, according to the first embodiment, thepower-dividing controlling means for bringing the planetary gear intomesh with a specified output gear on the basis of an output from theposition detecting means after the completion of the “initialpositioning” operation of the planetary gear with respect to thelimiting member, and causing the specified output gear to selectivelytransmit the driving power of the sun gear, is provided withinitial-positioning instructing means for causing the “initialpositioning” operation to be actively performed each time an element towhich power is to be transmitted is selected, only in an operation stepin which a series of desired photographic control steps of the camera isnot adversely affected (for example, the response speed of aphotographic operation is not impaired) even if the “initialpositioning” operation (the operation of meshing the planetary gear witha specified output gear) is carried out in addition to a power-dividingselection operation which is performed prior to an operation carried outby a mechanism to which power has been transmitted, such as filmwinding, film rewinding, backward or forward movement of a lens barrelor automatic loading, zooming. In the above-described arrangement, it ispossible to achieve power transmission with highly improved reliabilitywithout hindering a particular sequence of desired photographic controlsteps in the camera.

A second embodiment of the present invention will be described belowwith reference to FIGS. 37 to 40.

FIG. 37 is a schematic view showing the specific arrangement of aphotographic lens barrel to which power is transmitted by a powerdividing device through a zooming mechanism and a mechanism for moving alens barrel backward or forward, as well as the specific arrangement ofelements disposed in the vicinity of the photographic lens barrel.

In the arrangement shown in FIG. 37, a lens tube 53 includes a convexlens unit 51 and a concave lens unit 52, and is held on a cam ring 54and a lens barrel 55 by three pins 53 a.

Three cam grooves along which the lens tube 53 is to move and anotherthree cam grooves along which the concave lens unit 52 is made to moveare cut in a cylindrical wall of the cam ring 54. The cam ring 54 isrotatably supported by the lens barrel 55 and has a gear portion 54 awhich meshes with a zooming gear 58. The zooming gear 58 meshes with thefinal gear of a power transmission mechanism (zooming mechanism) (notshown) which is coupled to the output gear 9 c.

The lens barrel 55 is guided by a camera body (not shown) so that it canmove in the vertical direction only (along the optical axis) as viewedin FIG. 37. The lens barrel 55 has three rectilinear grooves 55 a intowhich the three pins 53 a of the lens barrel 53 are fitted,respectively. The lens barrel 55 also has an integrally formed codepattern 57 for detection of a zoom position. Further, the lens barrel 55has an internally threaded portion 55 c for retracting the lens barrel55 and a lock portion 55 b for preventing the lens barrel 55 fromretracting.

A code brush 56 is integrally arranged on the cam ring 54. As the camring 54 rotates, the code brush 56 slides on the code pattern 57 andtransmits to a control circuit which will be described later, compositefocal length information determined by the position of the convex lensunit 51 and that of the concave lens unit 52.

As de scribed above, the zooming gear 58 meshes with the final gear ofthe zooming mechanism coupled to the output gear 9 c. A shaft 58 a isrotatably supported by the camera body (not shown), and a gear portion58 b is meshed with a gear portion 54 a of the cam ring 54.

A helicoid gear 59 is rotatably supported on the camera body (not shown)by a shaft 59 a, and power is transmitted to the helicoid gear 59through a power transmission mechanism (a forward/backward lens-barrelmoving mechanism) (not shown) which is coupled to the output gear 9 a. Ahelicoid threaded portion 59 c is meshed with an internally threadedportion 55 c of the lens barrel 55, and moves a lens barrel unit(consisting of the elements 51 to 55) upward and downward along theoptical axis as viewed in FIG. 37, thereby performing a retractingoperation.

A lens-barrel-out switch 60 is arranged to be turned on when the lensbarrel unit (51 to 55) is placed in its forward position (in itsprojected state). A lens-barrel-in switch 61 is arranged to be turnedoff when the lens barrel unit (51 to 55) is placed in its retractedstate.

A bayonet lock lever 62 has a s lot 62 a and is supported movably towardthe right and the left as viewed in FIG. 37 by a shaft 64 of the camerabody (not shown) which is fitted into the slot 62 a. A rack portion 62 cis meshed with a bayonet gear 63.to which power is transmitted by apower transmission mechanism (a bayonet lock mechanism) (not shown)which is coupled to the output gear 9 b. A claw 62 b abuts a clawportion 55 b of the lens barrel 55 in the state shown in FIG. 37,thereby locking the lens barrel 55 so that it does not retract downwardas viewed in FIG. 37. The bayonet lock lever 62 has an arm 62 d at theother end, and in the state shown in FIG. 37, the arm 62 d abuts acentral common terminal of a bayonet switch 65 and carries the fact thatthe bayonet lock lever 62 is locked, to the control circuit which willbe described later. If the bayonet lock lever 62 moves from the positionof FIG. 37 toward the right and the claw 62 b disengages from the clawportion 55 b of the lens barrel 55, the arm 62 d transmits to thecontrol circuit the fact that the bayonet lock lever 62 is unlocked.

The specific arrangement of the power dividing device is similar to thatdescribed in connection with the first embodiment (refer to, forexample, FIGS. 2 and 3), and a description thereof is omitted.

FIG. 38 is a circuit block diagram showing the essential parts of acamera provided with the power dividing device.

The circuit shown in FIG. 38 includes a control circuit 501 forcontrolling various operations of the camera, an electrical power source502, a switch 503 which is turned on when a shutter release button ispressed, a switch 504 which is turned on when a telephoto zooming buttonis pressed, a switch 505 which is turned on when a wide-angle zoomingbutton is pressed, and a main switch 560 of the camera.

The shown circuit also includes a bayonet switch 507 (which correspondsto the bayonet switch 65 shown in FIG. 37) which is turned on or offwhen the bayonet lock lever 62 is locked or unlocked. From the state ofthe bayonet switch 507, it is determined whether the bayonet lock lever62 is locked, unlocked or in an intermediate state.

A lens-barrel-out switch 508 is turned on when the lens barrel 55 ismoved forward, while a lens-barrel-in switch 509 is turned on when thelens barrel 55 is retracted. The switches 508 and 509 correspond to theswitches 60 and 61 of FIG. 37.

A zoom-position switch 510 is turned on/off when the code brush 56 shownin FIG. 37 slides on the code pattern 57 with the rotation of the camring 54. The states of the lens tube 53 between the telephoto end andthe wide-angle end, as well as between an intermediate point of aretracting operation and the end thereof are identified on the basis ofthe combination of on and off of signals ZOOM1 to ZOOM4.

Photointerrupters 511 and 512 (which correspond to the photocoupler 17of FIGS. 2 and 3) detect the state of the rotating arm 5 of the powerdividing device on the basis of the rotational state of the pulse disc14. The photointerrupters 511 and 512 output a signal corresponding to atransition between brightness and darkness by detecting the bright anddark pattern segments provided on the pulse disc 14.

The motor 1 and the plunger 16 are similar to those shown in FIGS. 2 and3.

An operation for causing the lens barrel 55 to retract, executed by thecontrol circuit 501, will be described below with reference to theflowchart of FIG. 39.

This process is started in Step #100.

In Step #101, the output gear 9 c, that is, the zooming mechanism, isselected as an element to which power is to be transmitted, and themotor 1 is energized so that it rotates in the “Rv” direction, that is,in the direction of wide-angle zooming. At this time, if apower-dividing error is detected, the process proceeds from Step #102 toStep #105. Whether the operation at this time is the power-dividingerror is determined in the following manner: If the planetary gear 7 andthe output gear 9 c correctly mesh with each other, a “bright” pulse isinputted from the photocoupler 17, but if such a pulse is not inputted,it is determined that the power-dividing error has occurred. In Step#105, the “initial positioning” operation referred to in detail in thedescription of the power dividing device in the first embodiment iscarried out, and the process returns to Step #101. With this operation,it is possible to again perform the power dividing operation of Step#101 even if this operation fails due to a phenomenon which may occurduring the power dividing operation (specifically, “the operation ofselecting an element to which power is to be transmitted”) of Step #101,that is, due to a phenomenon in which a tooth tip of the output gearbites into that of the planetary gear 7 which was meshed with the outputgear before power dividing is started. In nearly all cases, it ispossible to restore an incorrect operation to a correct operation bycarrying out the above-described operation of performing the requiredsteps again.

If the process unconditionally returns to Step #101 at this time, theinfinite loop of repeating the same operation may occur in the case of astructural abnormality. To avoid this problem, it is preferable toattach a certain condition to the execution of Step #105, for example,“if a user of the camera operates any switch, the process returns fromStep #105 to Step #101” or “the process may automatically return fromStep #105 to Step #101 up to a predetermined number of times”.

If it is detected in Step #102 that the power dividing operation hassucceeded, the process enters the loop of Steps #103 to #104.

In Step #103, it is determined whether the lens tube 53 has reached thebackward end of its retracting path (hereinafter referred to as the“retracting end”), on the basis of the state of the zoom-position switch510. In the next step #104, a check is made on the time required for thelens tube 53 to reach the retracting end. The process repeats this loopuntil a time period indicative of the detection of an abnormal state (inthis case, two seconds) is reached. If the lens tube 53 reaches theretracting end in two seconds, the process proceeds from Step #103 toStep #106, where abutment energization is performed for bringing thelens tube 53 into full abutment with the retracting end. Then, theprocess proceeds to Step #107.

If it is detected from the state of the zoom-position switch 510 thatthe lens tube 53 has not yet reached the retracting end although twoseconds have passed in Step #104, that is, although the time requiredfor the lens tube 53 to reach the retracting end has passed, it isdetermined that an abnormality has occurred, and the process proceeds toStep #105. Such an abnormality is considered to be due to a number ofcauses: If a force is applied to the lens tube 53 from the outside, thelens tube 53 will operate abnormally, or even if the power dividingoperation is not correctly performed in Step #101, the process may enterthe loop of Steps #103 to #104 without detecting that fact(power-dividing error) (owing to, for example, the introduction ofexternal noise into the output of the photocoupler 17). For the aboveand other reasons, the “initial positioning” operation is performed inStep #105, the power dividing operation of Step #101 is performed again.

If the lens tube 53 correctly reaches the retracting end, the processproceeds to Step #107 as described above. In Step #107, the element towhich power to be transmitted is switched from the output gear 9 c tothe output gear 9 b, that is, to the side of the bayonet lock mechanism,and the motor 1 is energized so that it rotates in the “Fw” direction(in the direction of mesh release).

The operation at this time is described in more detail. First, theplunger 16 is energized and the motor 1 is energized to rotate in the“Fw” direction reverse to the “wide-angle” direction, whereby theplanetary gear 7 is made to disengage from the output gear 9 c coupledto the zooming mechanism. The bayonet gear 63 is located in the “Fw”direction and the direction of energization for unlocking of the bayonetlock lever 62 is “Fw”. Accordingly, when the position of the output gear9 b coupled to the bayonet lock mechanism is detected by thephotocoupler 17, the energization of the plunger 16 is stopped and theplanetary gear 7 and the output gear 9 b are made to mesh with eachother, and the energization for unlocking of the bayonet lock lever 62is started in turn.

If the aforesaid power-dividing error is detected during theabove-described operation, the process proceeds from Step #108 to Step#105. For example, if the planetary gear 7 does not completely exit fromthe crown stopper 10 and the holding stopper 11 and the power-dividingerror takes place, the motor 1 is energized to rotate in the “Fw”direction for the purpose of causing the planetary gear 7 to perform theaforesaid “exit operation”. As a result, during the operation shown inSteps #101 to #106, the motor 1 may be energized to rotate in the “Rv”direction, causing the lens tube 53 which has reached the retracting endto move forward. For this reason, to again energize the lens tube 53before the unlocking operation of the bayonet lock lever 62 is performedagain, the process returns to Step #105 as described above. By insertingthe “initial positioning” operation, it is possible to escape fromnearly all kinds of “power-dividing errors”.

If the power dividing operation of Step #107 is correctly performed, theprocess proceeds to the loop of Steps #109 to #110, where theenergization of the motor 1 is continued until the bayonet switch 65 isopened which changes its state in accordance with whether the bayonetlock lever 62 is locked or unlocked. If the bayonet switch 65 is opened,the process proceeds to Step #111, where abutment energization isperformed.

If one second, which is a time period indicative of the detection of anabnormality elapses before the bayonet switch 65 is opened, the processproceeds from Step #110 to Step #105. In this case as well, as describedin connection with Steps #103 to #104, not only the abnormality of thebayonet lock lever 62 or the bayonet lock mechanism but also a failure(power-dividing error) of the power dividing operation may have takenplace, and the state of the lens tube 53 may not be the same as thestate reached by the lens tube 53 at the time of the completion of step#106. For this reason, the process returns to Step #105, and theaforesaid series of operations starting with the drive of the lens tube53 is performed again.

If the operation of unlocking the bayonet lock lever 62 is completed inStep #111, the element to which power is to be transmitted is switchedfrom the output gear 9 b to the output gear 9 a, that is, to the side ofthe forward and backward lens-barrel moving mechanism, and the motor 1is energized so that the output gear 9 a can rotate in the “Rv”direction (retracting direction).

The operation at this time is described in more detail. First, theplunger 16 is energized and the motor 1 is energized to rotate in the“Rv” direction, whereby the planetary gear 7 is made to disengage fromthe output gear 9 b coupled to the bayonet lock mechanism. Subsequently,when it is detected that the planetary gear 7 has reached the middleposition between the output gear 9 b and the output gear 9 c coupled tothe zooming mechanism, the direction of energization of the motor 1 isswitched to the “Fw” direction. When the planetary gear 7 passes theposition of the output gear 9 b and then the position of the output gear9 a coupled to the forward/backward lens-barrel moving mechanism, thedirection of energization of the motor 1 is switched to the “Rv”direction. When the planetary gear 7 reaches the position of the outputgear 9 a, the energization of the plunger 16 is stopped to cause theoutput gear 9 a and the planetary gear 7 to mesh with each other.

If the aforesaid power-dividing error is detected during theabove-described operation, the process proceeds from Step #113 to Step#116. For example, if the planetary gear 7 does not exit from the crownstopper 10 and the holding stopper 11 and the power-dividing error takesplace, there is a strong possibility that the bayonet lock lever 62unlocked in the operation of Steps #107 to #111 may be displaced fromits unlocked position. In the power dividing operation, since theplanetary gear 7 does not pass the position of the output gear 9 ccoupled to the zooming mechanism, the possibility that the planetarygear 7 may move up to the lens tube 53 is not strong. In this case,accordingly, after the “initial positioning” operation has beenperformed in Step #116, the process proceeds to Step #107 and the seriesof operations starting with the operation of unlocking the bayonet locklever 62 is performed again.

If the power dividing operation is correctly performed in Step #112, theprocess proceeds to the loop of Steps #114 to #115. In this loop, theenergization of the motor 1 is continued until the lens-barrel-in switch509 (61) is turned on, the lens-barrel-in switch 509 (61) being turnedon when the lens barrel 55 reaches the retracted position. When theswitch 509 is turned on, abutment energization is performed in Step #117and the retracting operation is brought an end in Step #118.

If two seconds, which is a time period indicative of the detection of anabnormality elapses before the lens-barrel-in switch 509 is turned on,the process proceeds from Step #115 Step #116, and the “initialpositioning” operation is performed. In this case as well, as describedin connection with Steps #109 to #110, not only the abnormality of thelens barrel 55 or the forward/backward lens-barrel moving mechanism butalso a failure of the power dividing operation may have taken place.Accordingly, the process returns from Step #116 to Step #107 by the samereason as when the power-dividing error is detected in Step #113, andthe series of operations starting with the operation of unlocking thebayonet lock lever 62 is performed again.

As described above, a number of different steps for performing theseries of operations again are inserted at different positions in thesequence so that appropriate resetting can be performed for all possiblefailures which are expected to occur in the power dividing operation.Accordingly, it is possible to realize processing without condition fornearly all failures.

The operation of causing the lens barrel 55 to move forward, executed bythe control circuit 501, will be described below with reference to theflowchart of FIG. 40.

This operation is started in Step #200.

In Step #201, whether the bayonet lock lever 62 is in the unlocked stateis determined from the state of the bayonet switch 507 (65). If thestate of the bayonet switch 507 indicates that the bayonet lock lever 62is not in the unlocked state (the contact piece of the bayonet switch507 is open which is to be closed when the bayonet lock lever 62 isunlocked), the operation of unlocking the bayonet lock lever 62 isperformed in Steps #202 to #207, as described in connection with Steps#107 to #111 of FIG. 39. If the state of the bayonet switch 507indicates that the bayonet lock lever 62 is in the unlocked state (thecontact piece of the bayonet switch 507 is closed which is to be closedwhen the bayonet lock lever 62 is unlocked), the process proceeds toStep #208.

In Step #208, the element to which power is to be transmitted isswitched to the output gear 9 c, that is, to the side of the forward andbackward lens-barrel moving mechanism, and the motor 1 is energized sothat the output gear 9 c can rotate in the “Fw” direction (lens-barrelforward direction). In this operation, if a power-dividing error isdetected from the output of the photocoupler 17, the process proceedsfrom Step #209 to Step #206. In Step #206, the above-described “initialpositioning” operation for the power dividing device is performed, andthe process returns to Step #201. The requirement for executing theoperation of Step #206 is substantially the same as that described inconnection with Step #105.

If the power dividing operation is correctly performed in Step #209, theprocess enters the loop of Steps #210 and #211. In Step #210, whetherthe lens barrel 55 has moved forward up to a position where it can belocked by the bayonet lock lever 62 is determined from the state of thelens-barrel-out switch 508 (60). In Step #211, the time taken until theswitch 508 is turned on is measured, and the process repeats the loopuntil “two seconds”, i.e., a time period indicative of the detection ofan abnormality, elapses. If the switch 508 is turned on within “twoseconds”, abutment energization is performed in Step #212, and theprocess proceeds to the next step #213.

If “two seconds” elapses in Step #211, it is determined that anabnormality has occurred, and the process proceeds to Step #206. Theabnormality may be due to the abnormality of the lens tube 53, but itmay also be considered that although the power dividing operation hasnot been correctly performed in Step #208, the process has entered theloop of Steps #210 and #211 without detecting the power-dividing error.Accordingly, in Step #206, the “initial positioning” operation isperformed, and the series of operations starting with the power dividingoperation of Step #201 is performed again. Since the state of thebayonet lock lever 62 is again checked in Step #201, if the state of thebayonet lock lever 62 is changed in Step #208, it is possible to performappropriate processing.

If the lens barrel 55 reaches the position where it can be locked by thebayonet lock lever 62, the element to which power is to be transmittedis switched to the output gear 9 b, that is, to the side of the bayonetlock mechanism, and the motor 1 is energized so that the output gear 9 brotates in the “Rv” direction (lock direction).

The operation at this time is described in more detail. First, theplunger 16 is energized and the motor 1 is energized to rotate in the“Rv” direction reverse to the forward direction of the lens barrel 55,whereby the planetary gear 7 is made to disengage from the output gear 9a coupled to the zooming mechanism. The output gear 9 b coupled to thebayonet lock mechanism is positioned in the “Rv” direction in which aretracting output is produced, and the direction of rotation of thebayonet lock lever 62 is the “Rv” direction. Accordingly, when theposition of the output gear 9 b is detected through the photocoupler 17,the energization of the plunger 16 is stopped to cause the planetarygear 7 and the output gear 9 b to mesh with each other, and energizationfor bayonet lock is started in turn.

If a power-dividing error is detected during the above-describedoperation, the process proceeds from Step #214 to Step #206. Forexample, if the planetary gear 7 does not exit from the crown stopper 10and the holding stopper 11 and the power-dividing error takes place, themotor 1 is energized to rotate in the “Rv” direction during the “exitoperation” of the planetary gear 7. As a result, there is a possibilitythat the lens barrel 55 which has been moved forward by the energizationof the motor 1 in the “Fw” direction in the operation of Steps #210 to#212 may be made to move backward. In this case, however, if the powerdividing operation is simply performed again to cause the bayonet locklever 62 to perform the locking operation, no desired result may beobtained. This is because not only the bayonet lock lever 62 or thebayonet lock mechanism but also a failure of the power dividingoperation may have occurred, and there is also a possibility that thestate of the lens tube 53 may not be the same as the state reached bythe lens tube 53 at the time of the completion of Step #207. For thisreason, the process returns to Step #206, and the series of operationsstarting with the drive of the lens tube 53 is performed again. Asdescribed above, the series of operations starting with the operation ofmoving the lens barrel 55 forward is again performed while the processis proceeding through Steps #206→#201→#208, whereby it is possible toagain perform the locking operation of the bayonet lock lever 62.

If the power dividing operation is correctly performed in Step #213, theprocess proceeds from Step #214 to the loop of Steps #215 and #216. Inthe loop, the energization of the motor 1 is continued until the bayonetswitch 65 is locked. When the bayonet switch 65 is locked, the processproceeds to Step #217, where abutment energization is performed.

If one second, which is a time period indicative of the detection of anabnormality, elapses before the bayonet switch 65 is locked, the processproceeds from Step #216 Step #206. In this case as well, as described inconnection with steps #210 to #211, not only the abnormality of thebayonet lock lever 62 or the bayonet lock mechanism but also a failureof the power dividing operation may have taken place, and the state ofthe lens tube 53 may not be the same as the state reached by the lenstube 53 at the time of the completion of step #213. For this reason, theprocess returns to Step #206, and the aforesaid series of operationsstarting with the drive of the lens tube 53 is performed again.

If the locking operation of the bayonet lock lever 62 is completed inStep #217, the process proceeds to Step #218, where the element to whichpower dividing is to be directed is switched to the output gear 9 c,that is, the zooming mechanism, and the motor 1 is energized so that theoutput gear 9 c can rotate in the “Fw” direction (the telephotodirection).

The operation at this time is described in more detail. First, theplunger 16 is energized and the motor 1 is energized to rotate in the“Fw” direction, whereby the planetary gear 7 is made to disengage fromthe output gear 9 b coupled to the bayonet lock mechanism. Subsequently,when it is detected that the planetary gear 7 has reached the middleposition between the output gear 9 b and the output gear 9 a, thedirection of energization of the motor 1 is switched to the “Rv”direction. When the planetary gear 7 passes the position of the outputgear 9 b and then the position of the output gear 9 c, the direction ofenergization of the motor 1 is switched to the “Fw” direction. When theplanetary gear 7 reaches the position of the output gear 9 c, theenergization of the plunger 16 is stopped to cause the output gear 9 cand the planetary gear 7 to mesh with each other.

If a power-dividing error is detected during the above-describedoperation, the process proceeds from Step #219 to Step #206. Forexample, if the planetary gear 7 does not exit from the crown stopper 10and the holding stopper 11 and the power-dividing error takes place,there is a strong possibility that the bayonet lock lever 62 locked inthe operation of Steps #213 to #217 may be displaced from its lockedposition. If the lock by the bayonet lock lever 62 is imperfect, theaforesaid locking operation must be again performed. However, to lockthe bayonet lock lever 62 again, the lens barrel 55 must be moved up toits most forward position. To move the lens barrel 55 to the mostforward position by the energization of the motor 1, the bayonet locklever 62 must be completely unlocked. As a result, the following stepsare performed again: Step #206 to Steps #201 to #207 for unlocking thebayonet lock lever 62, Steps #208 to #212 for moving the lens barrel 55forward, and Steps #213 to #217 for again performing the lockingoperation of the bayonet lock lever 62.

More specifically, if a power-dividing error occurs in the operation ofStep #218, the process returns from Step #206 to Step #201 and theunlocking operation of the bayonet lock lever 62 is performed asdescribed in connection with Steps #107 to #111 of FIG. 39. The outlineof the unlocking operation is stated below. In Step #201, it is checkedwhether the bayonet lock lever 62 is unlocked. If the bayonet lock lever62 is not unlocked, the element to which power is to be transmitted isswitched to the bayonet lock mechanism in Step #202. In Step #203, it isdetected whether a power-dividing error has occurred, and in the loop ofSteps #204 and #205, the state of the bayonet switch 507 is checked. InStep #207, abutment energization is performed, and the process returnsto the ordinary flow shown in Step #208 and the subsequent steps.

If the power dividing operation of Step #218 is correctly performed, theprocess proceeds to the loop of Steps #220 and #221. In this loop, theenergization of the motor 1 is continued until the lens tube 53 reachesthe wide-angle end. If the zoom-position switch 510 is set to itswide-angle end position, the motor 1 is energized for braking the lenstube 53 in Step #222, and the forward lens-barrel moving operation isbrought to an end in Step #223. If two seconds, which is a time periodindicative of the detection of an abnormality, elapses before thezoom-position switch 510 is set to the wide-angle end position, theprocess proceeds from Step #221 to #206, and the “initial positioning”operation is performed. In this case as well, not only the abnormalityof the lens tube 53 or the zooming mechanism but also a failure of thepower dividing operation may have taken place. Accordingly, the processreturns to Step #206 by the same reason as when the power-dividing erroris detected in Step #218, and the series of operations starting with thelocking operation of the bayonet lock lever 62 is performed again.

According to the second embodiment described above, in a camera which isarranged to execute a sequence of photographic operations whileperforming power dividing and transmitting the divided power toindividual mechanisms sequentially in time by using a power dividingdevice, part of the mechanisms occasionally do not operate correctly. Atypical cause of such an incorrect operation is as follows: During apower dividing operation, if a tooth tip of the planetary gear 7 bitesinto any one of the output gears 9 a to 9 d or a force is applied fromthe outside, an abnormality may occur in a photographic lens barrel partor in a power transmission mechanism for transmitting the output of theoutput gear to the photographic lens barrel part. Otherwise, in themethod of identifying the position of the planetary gear 7 duringrevolution on the basis of the output of a single photocoupler 17, noisemay be introduced into the output of the photocoupler 17 and a detectionerror may occur. It has been experimentally found that nearly all of theabove-described mechanical abnormalities can be solved by performing the“initial positioning” operation and performing the required steps again.Further, even if the fact that a particular operation was not correctlyperformed owing to a detection error due to noise is detected during asubsequent operation, it is possible to restore the incorrect operationto a correct operation by performing the required steps again (since theprobability that noise is introduced under the same conditions isextremely low). For the above-described reasons, it is determined whichof the mechanism is operating when an abnormality occurs, and it isdetermined in which step of the entire process a restoration operation(the operation of again performing the required steps including the“initial positioning” operation) should be started. (The process is notalways started all over again, that is to say, after the process isreturned to the step in which the abnormality may have occurred, therestoration operation is started in that step.) The series ofphotographic operations can be made to proceed from the thus-determinedstep to the last step.

Accordingly, in spite of an inexpensive and compact arrangement using anerror-free expensive part or large-scale device, if a failure such asthe above-described one takes place, it is possible to automaticallyeliminate the failure so that the photographic sequence can be made tosecurely proceed up to the last step in the minimum required time.Accordingly, it is possible to achieve an extremely effective powerdividing device.

As described above, according to the second embodiment, there isprovided an arrangement including detection-signal generating means fordetecting a plurality of states of operation, identifying means foridentifying the state of progress of the operation on the basis of thestate of generation of a detection signal from the detection-signalgenerating means, restoration selecting means for selecting a method ofrestoration from a malfunction on the basis of both a signal indicativeof the malfunction which is generated from the detection-signalgenerating means and the state of progress of the operation identifiedby the identifying means. If the operation is not correctly performed, arestoration operation is started in the last operational step in whichthe operation was correctly executed, according to the state of progressof the operation at that time. Accordingly, in an arrangement in which aseries of photographic operations can be completed by performing aplurality of operations, even if a particular operation is not correctlyperformed, the operation error can be automatically eliminated and thephotographic operations can be made to securely proceed to the last stepin the minimum required time.

A third embodiment will be described with reference to FIG. 41. Thethird embodiment differs from the first embodiment merely in the designof a flowchart showing the operation of the control circuit, and onlydifferent steps will be described below. In the flowchart of FIG. 41,the same step numbers are used to denote steps which are identical tothose explained in connection with the first embodiment, and descriptionthereof is omitted.

Step #311: It is determined whether the shutter release button has beenoperated up to the first stroke position and a photography readinessswitch has been turned on. If the photography readiness switch has beenturned on, the process proceeds to Step #312.

Step #312: An AE circuit (not shown) is operated to obtain lightmeasurement information.

Step #313: An AF circuit (not shown) is operated to obtain distancemeasurement information.

Step #314: It is determined whether the shutter release button has beenoperated up to the second stroke position and a shutter release switchhas been turned on. If the shutter release switch has been turned on,the process proceeds to Step #315.

Step #315: A stepping motor (not shown) is driven on the basis of thedistance measurement information obtained in Step #312, thereby settinga third-group lens to a predetermined position. Then, the processproceeds to Step #84.

Step #84: A shutter opening and closing operation is performed on thebasis of the light measurement information obtained in Step #312, andexposure of a film is performed. Then, the process proceeds to Step#161.

Steps #161 to #165: winding of the film is performed. As describedabove, in the third embodiment, since the film winding operation isperformed immediately after the completion of exposure of the film, itis possible to confirm the completion of the photography upon thecompletion of the exposure operation.

Step #86: It is determined whether the film is in a stretched state. Ifit is in the stretched state, the process proceeds to Step #317;otherwise, the process proceeds to Step #316.

Step #316: The stepping motor is driven to reset the third-group lens toits initial position. The process proceeds to Step #87.

Step 317: The stepping motor is driven to reset the third-group lens tothe initial position. The process proceeds to Step #91.

According to the third embodiment, as is readily understood from FIG.41, a sequence for generating a drive sound which makes it possible fora photographer to confirm the completion of photography is inserted at apoint in time as close as possible to the time when the shutter releasebutton reaches the second stroke position (the shutter release switch isturned on). More specifically, after a shutter opening and closingoperation, a film winding operation is performed prior to the resettingof the photographic lens to the initial position so that the drive soundcan be generated at a time as close as possible to the time when theshutter release button reaches the second stroke position. Accordingly,a physical sensation experienced by the photographer when he/sheoperates the shutter release button is improved, whereby thephotographer can perform photography without anxiety.

The third embodiment has been described with reference to a system usinga three-group zoom lens arrangement whose third-group lens is used forfocusing. However, the present invention is not limited to such asystem, and can of course be applied to a wide variety of cameras usingautofocus devices, such as a camera using a two-group zoom lensarrangement whose first-group lens is used for focusing and a camerausing a single-focus lens.

As described above, according to the third embodiment, there is providedan arrangement including restoration operation instructing means forinstructing lens-position controlling means to execute the operation ofrestoring the photographic lens to its initial position after thecompletion of a film winding operation which is performed by filmtransporting means after the completion of an exposure operation. Insuch an arrangement, the film winding operation which is capable ofgenerating a drive sound indicative of the completion of the photographyis executed immediately after the completion of the exposure operation,and the photographic lens is then restored to the initial position.Accordingly, the physical sensation of a photographer for a shutterrelease operation is improved, whereby the photographer can performphotography without anxiety.

A fourth embodiment will be described below with reference to FIGS. 42to 44. In the following description, reference is made to only the partsof the fourth embodiment which differ from those of the firstembodiment.

FIG. 42 is a schematic view showing the essential circuit blocks andmechanical parts of a camera.

The camera shown in FIG. 42 includes the plunger driving circuit 21 forturning on or off the plunger 16, the pulse signal detecting circuit 22for detecting the output pulse of the photocoupler 17, and the motordriving circuit 23 for turning on or off the motor 1 shown in severalfigures such as FIG. 1 and for providing control of rotation relative tothe “Rv” direction and rotation relative to the “Fw” direction. Thecircuits 21, 22 and 23 are controlled by the control circuit 24. Theshown camera also includes the output gears 9 a to 9 d describedpreviously, and the power of a desired one of the output gears 9 a to 9d is transmitted to the corresponding one of the mechanisms (thelens-barrel driving system and the film-transportation driving system)25 a to 25 d through the associated gear train (not shown butrepresented by a thick line), as described previously with reference toFIG. 16. The resultant drive signal 26 a, 26 b, 26 c or 26 d is fed backto the control circuit 24. The shown camera also includes therevolution-of-planetary-gear lock mechanism 27 made up of elements suchas the arm 15, the rotation-stopping arm 12, the crown stopper 10 andthe holding stopper 11.

An element AND is an AND gate having two inputs, and the state signalsof a telephoto switch (TELEPHOTO SW) and a wide-angle switch (WIDE-ANGLESW) which are operated for zooming are inputted to the respective inputterminals. An element FF is an RS flip-flop, and the output signal ofthe AND gate AND and the state signal of a shutter release switch(shutter release SW) of the camera are inputted to the respective inputterminals (low active) of the RS flip-flop.

The outline of the fourth embodiment will be described below before adescription of the operation of the part of the control circuit 24 whichis associated with the present invention.

If the motor 1 is stopped with the planetary gear 7 remaining in meshwith an arbitrary one of the output gears 9 a to 9 d, a gear trainextending from the output gear in mesh is prevented from idling and themechanism of an element to which power is to be transmitted can belocked, whereby occurrence of an unwanted operation can be prevented. Inthe fourth embodiment, one example of such a process is performed duringnormal photography (the main switch off). More specifically, when themain switch is on, the planetary gear 7 remains in mesh with the gear 9c which is coupled to the zoom driving gear 312. In a zooming operation,the motor 1 is driven to rotate in the “Fw” or “Rv” direction with theplanetary gear 7 in mesh with the gear 9 c. When film winding after ashutter release operation is to be performed, the planetary gear 7 ismade to mesh with the output gear 9 d coupled to the film-transportationdriving system for the purpose of performing the film winding. After thecompletion of the film winding, the planetary gear 7 is again made tomesh with the output gear 9 c.

The reasons why the above-described operation is needed are that what anoperator can easily touch among the mechanism parts of the camera whenthe main switch is on is the lens barrel 314 or the lens tube 316 shownin FIG. 16 referenced previously in connection with the firstembodiment, and that the lens barrel 316 easily moves at a touch.However, in the state wherein the planetary gear 7 is in mesh with theoutput gear 9 c, the lens barrel 314 does not move since it is fixed bythe bayonet ring 311.

Actual film transportation in such gear locking and gear locking for thezoom driving gear 312 during a zooming operation will be described belowwith reference to FIG. 44.

When the main switch is on, the planetary gear 7 is meshed with theoutput gear 9 c coupled to the zoom driving gear 312 so that the lenstube 316 shown in FIG. 16 is prevented from moving owing to an externalforce. It is assumed here that the rotation of the motor 1 (the sun gear6) in the “Fw” direction corresponds to the energization of the motor 1in the telephoto direction or the rotation thereof in the direction offilm winding, while the rotation of the motor 1 (the sun gear 6) in the“Rv” direction corresponds to the energization of the motor 1 in thewide-angle direction or the rotation thereof in the direction of filmrewinding.

Normally, the planetary gear 7 is meshed with the output gear 9 c andperforms a zooming operation in accordance with the rotation of themotor 1. For example, in a case where the zooming operation iscontrolled by a zooming driving method based on energization with theplanetary gear 7 biased to a telephoto side, when the zooming operationis completed, the end portion 12 c of the rotation-stopping arm 12 isstopped in abutment with the “Fw”-side face of a cutout of the crownstopper 10, that is, the end face 10 a-1 shown in FIG. 44.

If a shutter release operation is performed, the planetary gear 7revolves in the “Rv” direction while performing the operation ofselecting an element to which power dividing is to be directed, andmeshes with the output gear 9 d in the same direction. Therotation-stopping arm 12 comes into abutment with an end face 10 b-2 ofan adjacent cutout of the crown stopper 10. Subsequently, the rotationof the planetary gear 7 in the “Rv” direction is transmitted to theoutput gear 9 d so that a film winding operation is performed throughthe planetary gear 304 for film transportation.

After the completion of the film winding operation, to prevent theoutput gear 9 c for zoom driving from idling, the planetary gear 7revolves while performing the operation of selecting an element to whichpower dividing is to be directed, and meshes with the output gear 9 c.When the planetary gear 7 meshed with the output gear 9 c, the rotationof the motor 1 is stopped. At this time, the following operation isneeded: The planetary gear 7 meshes with the output gear 9 c whilerevolving in the “Fw” direction, and when the end portion 12 c of therotation-stopping arm 12 enters the area between the end faces 10 a-1and 10 b-1 of the cutout of the crown stopper 10, the rotation of themotor 1 is stopped.

However, in the fourth embodiment, since the pulse disc 14 and thephotocoupler 17 are used to detect both the position of the planetarygear 7 during revolution and a signal to establish timing to turn on andoff the plunger 16 which limits and releases the revolution of theplanetary gear 7, it is necessary to continuously execute both theoperation of selecting through the revolution of the planetary gear 7 anelement to which power dividing is to be directed and the operation ofrotating the succeeding element to which power is to be transmitted, asdescribed in connection with the “entrance operation”.

Accordingly, it is necessary to stop the rotation of the motor 1 underpredictive control based on the prediction of the stop of the revolutionof the planetary gear 7, that is, the prediction of the entrance of theend portion 12 c of the rotation-stopping arm 12 into the area betweenthe end faces 10 a-1 and 10 d-1 of the cutout of the crown stopper 10.In this case, there are three cases depending on timing to stop themotor 1:

1) The motor 1 is stopped at the same time that the revolution of theplanetary gear 7 is stopped.

2) Even after the revolution of the planetary gear 7 in the “Fw”direction has been stopped, the rotation of the motor 1 is not stoppedand the output gear 9 c is made to rotate in a telephoto drivingdirection (in the “Fw” direction), and the lens tube 316 is moved.

3) Before the revolution of the planetary gear 7 is stopped, therotation of the motor 1 is stopped and the end portion 12 c of therotation-stopping arm 12 is left on the holding stopper 11, and theplanetary gear 7 becomes unable to revolve.

In the case 1), there is no problem. Regarding the case 2), it isinconvenient in practical use that the lens tube 316 moves each time afilm winding operation is performed. For this reason, the rotation ofthe motor 1 must be stopped by using timing of as short duration aspossible, but in this case, the case 3) may occur. In the case 3), thestate of operation after the completion of film transportation may seemto be normal on the camera side. However, subsequently, if a zoomingoperation is performed, the following operations will be encountered:

a) In the case of driving in the telephoto direction, the planetary gear7 revolves in the “Fw” direction until the end portion 12 c of therotation-stopping arm 12 enters the cutout of the crown stopper 10, andsubsequently a normal driving operation in the telephoto direction canbe performed.

b) In the case of driving in the wide-angle direction, the planetarygear 7 meshes with the output gear 9 d while revolving in the “Rv”direction, and causes the output gear 9 d to rotate in the film-windingdirection.

The operation of the case b) is not a correct operation. To cope withthe case b), in the fourth embodiment, the following control isperformed.

After the completion of film transportation, instead of stopping therotation of the motor 1 by using such timing that the occurrence of thecase 2) can be prevented, the case 3) is assumed to take place as theworst case and the following process is performed. If a signalindicative of driving in a wide-angle direction arrives, the motor 1 isdriven to rotate in the “Fw” direction during a slight period, to makethe planetary gear 7 revolve in the “Fw” direction. The planetary gear 7meshes with the output gear 9 c and the end portion 12 c of therotation-stopping arm 12 enters the area between the end faces 10 a-1and 10 d-1 of the cutout of the crown stopper 10, thereby causing therevolution of the planetary gear 7 to stop. Then, the motor 1 is drivento rotate in the wide-angle driving direction, i.e., in the “Rv”direction. In this case, the slight period during which the motor 1 isdriven to rotate in the “Fw” direction must be longer than the timingduring which the end portion 12 c of the rotation-stopping arm 12 entersfrom the state of FIG. 44 into the cutout of the crown stopper 10 (thearea between the end faces 10 a-1 and 10 d-1), but shorter than thetiming during which the operation of the planetary gear 7 is switchedfrom revolution to rotation and the backlash of a gear train extendingto the lens tube 316 which constitutes a zoom barrel is biased in thetelephoto driving direction and the lens tube 316 starts moving in thetelephoto direction.

As described above, it is assumed that no correct limitation of therevolution of the planetary gear 7 is performed (it is assumed that theend portion 12 c of the rotation-stopping arm 12 is located on theholding stopper 11 as shown in FIG. 44) in the case of applying gearlocking to the zooming mechanism, that is, in the case of performing theoperation of applying gear locking to the lens tube 316 which is locatedin, for example, the middle position between the telephoto end and thewide-angle end so that the zoom position of the lens tube 316 is notmoved. On the above-described assumption, the control of causing therotation-stopping arm 12 to enter the cutout of the crown stopper 10 isnecessarily inserted before the start of power transmission, whereby thereliability of the gear lock mechanism can be improved.

To achieve the above-described operations, it is necessary to detectwhether the signal indicative of driving in the wide-angle directionarrives “after the element to which power dividing is to be directed hasbeen switched to the side of the zooming mechanism, that is, from theoutput gear 9 d to the output gear 9 c, after the completion of filmwinding following a normal shutter release operation” (If the previousoperation is the same zooming operation, it is not necessary to performinstantaneous driving in the telephoto direction). A circuit part fordetecting the state of the previous operation is constituted by the ANDgate and the RS flip-flop FF which are shown in FIG. 42.

When the telephoto switch (TELEPHOTO SW) or the wide-angle switch(WIDE-ANGLE SW) are turned on to start an associated zooming operation,the output of the AND gate AND is inverted to a low level and the RSflip-flop is set. An output ZM provided at an output terminal Q of theRS flip-flop is set to a high level. If a shutter release operation isperformed, the shutter release switch is turned on, and the RS flip-flopFF is set and the output ZM at the output terminal is reset to a lowlevel. Accordingly, the output ZM is checked during a wide-angle zoomingoperation, and if the high level is detected, this indicates that theprevious output is a zooming operation, while if the low level isdetected, this indicates that the previous operation is a normal shutterrelease operation.

The operation of the above-described control circuit 24 will bedescribed below with reference to the flowchart of FIG. 43.

The process jumps to this flow from the step of a “wide-angle zooming”operation in a main flow which is not shown.

Step #421: A direction M of rotation of the motor 1 is set to the “Rv”direction.

Step #422: It is determined whether the previous operation is a zoomingoperation or a shutter release operation, from the output ZM of theabove-described RS flip-flop. If ZM=H, that is, if the previousoperation is a zooming operation, the process proceeds to Step #427. IfZM=L, that is, if the previous operation is a shutter release operation,the process proceeds to Step #423.

Step #423: To drive the motor 1 to rotate in the direction “Fw”direction, the direction of rotation of the motor 1 is set to “M=Fw”.

Step #424: An internal timer is started.

Step #425: The motor 1 is driven to rotate in the “Fw” direction tocause the planetary gear 7 to revolve in the “Fw” direction.

Step #426: It is determined whether the internal timer has counted apredetermined time. If the internal timer has not completed counting,the process returns to Step #425. Subsequently, if it is determined thatthe predetermined time has elapsed, the planetary gear 7 meshes with theoutput gear 9 c to cause the end portion 12 c of the rotation-stoppingarm 12 to enter the area between the end faces 10 a-1 and 10 d-1 of thecorresponding cutout of the crown stopper 10. It is determined that theplanetary gear 7 has stopped revolving, and the process proceeds to Step#427.

Step #427: To perform a wide-angle zooming operation, the motor 1 isdriven to rotate in the “Rv” direction.

Step #428: It is determined from the state of a switch (not shown)whether the lens tube 316 has reached the wide-angle end. If it has notreached the wide-angle end, the process proceeds to Step #429:otherwise, the process proceeds to Step #430.

Step #429: It is determined whether the wide-angle switch (WIDE-ANGLESW) is on or off. If the wide-angle switch (WIDE-ANGLE SW) remains on,the process returns to Step #428.

Step #430: Since lens tube 316 has reached the wide-angle end or adesired wide-angle zoom position and the wide-angle switch (WIDE-ANGLESW) has been turned off, the energization of the motor 1 is stopped.

In the fourth embodiment, if the lens tube 316 which constitutes thezoom barrel is located in a freely operable position between thetelephoto end and the wide-angle end, the operation of applying gearlocking to the zooming mechanism so that the zoom barrel 316 does notmove in that position is executed. However, on the assumption that thegear locking of the motor 1 may not be correctly achieved as shown inFIG. 44, the control of causing the rotation-stopping arm 12 tonecessarily enter the cutout of the crown stopper 10 before the start ofpower transmission in the wide-angle direction is carried out.Accordingly, it is possible to improve the reliability of the gear lockmechanism. Specifically, it is possible to prevent the planetary gear 7from erroneously meshing with the output gear 9 d for filmtransportation and performing film winding during a driving operation inthe wide-angle direction.

As described above, according to the fourth embodiment, there isprovided an arrangement including instructing means for instructingpower-dividing controlling means to bring a planetary gear into meshwith an output gear coupled to a power transmission mechanism which maybe subjected to an external force by accident, and simultaneously tostop power transmission to the output gear, after the completion of thepower transmission, and mesh controlling means for performing theoperation of again bringing the planetary gear 7 into mesh with theoutput gear before the start of power transmission to the output gearcoupled to the power transmission mechanism which may be subjected to anexternal force by accident. In the above-described arrangement, theplanetary gear 7 is made to again mesh with the output gear before thestart of power transmission to the output gear coupled to the powertransmission mechanism which may be subjected to an external force byaccident. Accordingly, even if the operation of meshing the planetarygear with the output gear coupled to the power transmission mechanism,which may be accidentally subjected to an external force, in accordancewith an instruction given by the instructing means, is not correctlyperformed, such an operation is performed again in a similar manner, sothat the power transmission to the output gear is started after thegears have securely meshed with each other. Accordingly, it is possibleto prevent unexpected movement of a mechanism which may be subjected toan external force by accident. In addition, a subsequent powertransmission operation can be reliably performed.

What is claimed is:
 1. A power transmission apparatus, comprising: afirst rotation portion which is rotatable and transmits a driving powerby rotation thereof; a second rotation portion which is rotatable andrevolves around said first rotation portion in association with rotationof said first rotation portion; a plurality of operation systems, eachof which is selectively engagable with said second rotation portion byrevolution of said second rotation portion around said first rotationportion, so as to receive the driving power from said first rotationportion; a restriction device which restricts revolution of said secondrotation portion around said first rotation portion; a determinationdevice which determines a revolution position of said second rotationportion relative to said first rotation portion; and a control devicewhich rotates said first rotation portion so as to cause said secondrotation portion to revolve around said first rotation portion to aposition where said second rotation portion engages a predeterminedoperation system of said plurality of operation systems when said firstrotation portion finishes a driving operation, and controls saidrestriction device so as to regulate revolution of said second rotationportion through to the position where said second rotation portionengages the predetermined operation system in accordance with adetermination of said determination device.
 2. A power transmissionapparatus according to claim 1, further comprising a motor whichgenerates the driving power.
 3. A power transmission apparatus accordingto claim 1, wherein said determination device includes an opticaldetection device which detects the revolution position of said secondrotation portion.
 4. A power transmission apparatus according to claim1, wherein said restriction device includes an electromagnetic drivingdevices.
 5. A power transmission apparatus according to claim 1, whereinsaid restriction device holds said second rotation portion so as toprevent revolution of said second rotation portion around said firstrotation portion.
 6. A power transmission apparatus according to claim1, wherein said predetermined operation system includes an optical unitdriving system.
 7. A power transmission apparatus according to claim 1,wherein said predetermined operation system includes a lens drivingsystem.
 8. A power transmission apparatus according to claim 1, whereinsaid predetermined operation system includes a focal length changingsystem.
 9. A power transmission apparatus according to claim 1, whereinsaid predetermined operation system includes a zoom system.
 10. A powertransmission apparatus according to claim 1, wherein said predeterminedoperation system includes a lens barrel system.
 11. A power transmissionapparatus according to claim 1, wherein said predetermined operationsystem includes an image recording medium transportation system.
 12. Apower transmission apparatus according to claim 1, wherein saidpredetermined operation system includes a camera.
 13. A powertransmission apparatus, comprising: a first rotation portion which isrotatable and transmits a driving power by rotation thereof; a secondrotation portion which is rotatable and revolves around said firstrotation portion in association with rotation of said first rotationportion; a plurality of operation systems, each of which is selectivelyengagable with said second rotation portion by revolution of said secondrotation portion around said first rotation portion, so as to receivethe driving power from said first rotation portion; a restriction devicewhich restricts revolution of said second rotation portion around saidfirst rotation portion; a determination device which determines arevolution position of said second rotation portion relative to saidfirst rotation portion; and a control device which rotates said firstrotation portion so as to cause said second rotation portion to revolvearound said first rotation portion to a position where said secondrotation portion engages a predetermined operation system of saidplurality of operation systems when said first rotation portion finishesa driving operation, and causes said restriction device to inhibitfurther revolution of said second rotation portion at the position wheresaid second rotation portion engages said predetermined operationsystem, wherein said control device controls said restriction device soas not to prevent revolution of said second rotation portion at aposition where said second rotation portion engages an operation systemdifferent from said predetermined operation system of said plurality ofoperation system in accordance with a determination of saiddetermination device.
 14. A power transmission apparatus according toclaim 13, further comprising a motor which generates the driving power.15. A power transmission apparatus according to claim 13, wherein saiddetermination device includes an optical detection device which detectsthe revolution position of said second rotation portion.
 16. A powertransmission apparatus according to claim 13, wherein said regulationdevice includes an electromagnetic driving device.
 17. A powertransmission apparatus according to claim 13, wherein said restrictiondevice holds said second rotation portion so as to prevent revolution ofsaid second rotation portion around said first rotation portion.
 18. Apower transmission apparatus according to claim 13, wherein saidpredetermined operation system includes an optical unit driving system.19. A power transmission apparatus according to claim 13, wherein saidpredetermined operation system includes a lens driving system.
 20. Apower transmission apparatus according to claim 13, wherein saidpredetermined operation system includes a focal length changing system.21. A power transmission apparatus according to claim 13, wherein saidpredetermined operation system includes a zoom system.
 22. A powertransmission apparatus according to claim 13, wherein said predeterminedoperation system includes a lens barrel system.
 23. A power transmissionapparatus according to claim 13, wherein said predetermined operationsystem includes an image recording medium transporting system.
 24. Apower transmission apparatus according to claim 13, wherein saidpredetermined operation system includes a camera.
 25. A powertransmission apparatus, comprising: a first rotation portion which isrotatable and transmits a driving power by rotation thereof; a secondrotation portion which is rotatable and revolves around said firstrotation portion in association with rotation of said first rotationportion; at least three operation systems, each of which is selectivelyengagable with said second rotation portion by revolution of said secondrotation portion around said first rotation portion, so as to receivethe driving power from said first rotation portion; a control devicewhich causes said first rotation portion to rotate so as to cause saidsecond rotation portion to revolve around said first rotation portion toa position where said second rotation portion engages a predeterminedoperation system of the at least three operation systems when said firstrotation portion finishes a driving operation; and a restriction devicewhich inhibits further revolution of said second rotation portion at theposition to which said second rotation portion is caused to revolve bysaid control device so as to engage the predetermined operation system.26. A power transmission apparatus according to claim 25, furthercomprising a motor which generates the driving power.
 27. A powertransmission apparatus according to claim 25, wherein said restrictiondevice includes an electromagnetic driving device.
 28. A powertransmission apparatus according to claim 25, wherein said restrictiondevice holds said second rotation portion so as to prevent revolution ofsaid second rotation portion around said first rotation portion.
 29. Apower transmission apparatus according to claim 25, wherein saidpredetermined operation system includes an optical unit driving system.30. A power transmission apparatus according to claim 25, wherein saidpredetermined operation system includes a lens driving system.
 31. Apower transmission apparatus according to claim 25, wherein saidpredetermined operation system includes a focal length changing system.32. A power transmission apparatus according to claim 25, wherein saidpredetermined operation system includes a zoom system.
 33. A powertransmission apparatus according to claim 25, wherein said predeterminedoperation system includes a lens barrel system.
 34. A power transmissionapparatus according to claim 25, wherein said predetermined operationsystem includes an image recording medium transporting system.
 35. Apower transmission apparatus according to claim 25, wherein saidpredetermined operation system includes a camera.